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Collections, Part Two

Collections, Part Two

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Page 1: Collections, Part Two

Collections Part Two

Outline for Today

Stacks Pancakes meets parsing

Queues Playing some music

Stack

This car canrsquot leavehellipThis car

canrsquot leavehellip

hellip until these two do

hellip until these two do

Thanks to Nick Troccoli for this example

Thanks to Nick Troccoli for this example

Any new car precedes all the old cars Only this car

can leave

Any new car precedes all the old cars Only this car

can leave

Thanks to Nick Troccoli for this example

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 2: Collections, Part Two

Outline for Today

Stacks Pancakes meets parsing

Queues Playing some music

Stack

This car canrsquot leavehellipThis car

canrsquot leavehellip

hellip until these two do

hellip until these two do

Thanks to Nick Troccoli for this example

Thanks to Nick Troccoli for this example

Any new car precedes all the old cars Only this car

can leave

Any new car precedes all the old cars Only this car

can leave

Thanks to Nick Troccoli for this example

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 3: Collections, Part Two

Stack

This car canrsquot leavehellipThis car

canrsquot leavehellip

hellip until these two do

hellip until these two do

Thanks to Nick Troccoli for this example

Thanks to Nick Troccoli for this example

Any new car precedes all the old cars Only this car

can leave

Any new car precedes all the old cars Only this car

can leave

Thanks to Nick Troccoli for this example

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 4: Collections, Part Two

This car canrsquot leavehellipThis car

canrsquot leavehellip

hellip until these two do

hellip until these two do

Thanks to Nick Troccoli for this example

Thanks to Nick Troccoli for this example

Any new car precedes all the old cars Only this car

can leave

Any new car precedes all the old cars Only this car

can leave

Thanks to Nick Troccoli for this example

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 5: Collections, Part Two

Thanks to Nick Troccoli for this example

Any new car precedes all the old cars Only this car

can leave

Any new car precedes all the old cars Only this car

can leave

Thanks to Nick Troccoli for this example

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 6: Collections, Part Two

Thanks to Nick Troccoli for this example

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 7: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 8: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 9: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

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(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 10: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 11: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

137

42

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 12: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 13: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

271

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 14: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 15: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

271

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

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Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 16: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 17: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 18: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

42

137

0

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 19: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 20: Collections, Part Two

Stack

A Stack is a data structure representing a stack of things

Objects can be pushed on top of the stack or popped from the top of the stack

0

42

137 Only the topmost element of a Stack can be accessed

Do you see why we call it the call stack and talk about stack frames

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 21: Collections, Part Two

An Application Balanced Parentheses

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 22: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 23: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 24: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 25: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 26: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
  • Slide 2
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Page 27: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 28: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 29: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 30: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 31: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 32: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 33: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 34: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 35: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 36: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

  • Slide 1
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Page 37: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 38: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 39: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 40: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 41: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 42: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 43: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 44: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 45: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 46: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 47: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 48: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 49: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 50: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 51: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 52: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 53: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 54: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 55: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 56: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 57: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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Page 58: Collections, Part Two

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

[

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

(

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1 ^

Balancing Parentheses

int foo() if (x (y + z[1]) lt 137) x = 1

Balancing Parentheses

( [ ) ]

Balancing Parentheses

( [ ) ]^

Balancing Parentheses

( [ ) ]^

(

Balancing Parentheses

( [ ) ] ^

(

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Balancing Parentheses

( [ ) ] ^

(

[

Oops Wrong type of parenthesis here

Oops Wrong type of parenthesis here

Balancing Parentheses

( (

Balancing Parentheses

( (^

Balancing Parentheses

( (^

(

Balancing Parentheses

( ( ^

(

Balancing Parentheses

( ( ^

(

(

Balancing Parentheses

( (

(

(

Balancing Parentheses

( (

(

(

Oops We never matched this

Oops We never matched this

Balancing Parentheses

)

Balancing Parentheses

)^

Balancing Parentheses

)^

Oops Therersquos nothing on the stack

to match

Oops Therersquos nothing on the stack

to match

Our Algorithm

For each character If itrsquos an open parenthesis or brace push it

onto the stack If itrsquos a close parenthesis or brace

ndash If the stack is empty report an errorndash If the character doesnrsquot pair with the character

on top of the stack report an error

At the end return whether the stack is empty (nothing was left unmatched)

More Stack Applications

Stacks show up all the time in parsing recovering the structure in a piece of text Often used in natural language processing take CS224N for

details Used all the time in compilers ndash take CS143 for details Therersquos a deep theorem that says that many structures

appearing in natural language are perfectly modeled by operations on stacks come talk to me after class if yoursquore curious

Theyrsquore also used as building blocks in larger algorithms for doing things like making sure a cityrsquos road networks are navigable (finding

strongly connected components take CS161 for details) and searching for the best solution to a problem ndash stay tuned

Time-Out for Announcements

Assignment 1

Assignment 1 is due this Friday at the start of class

Have questions Call into the LaIR Ask on EdStem Email your section leader

Discussion Sections

Discussion sections have started You should have received an email with your section time and section leaderrsquos name

Donrsquot have a section You can sign up for any open section by visiting

cs198stanfordedu

logging in via ldquoCS106 Sections Loginrdquo and picking a section of your choice

Get Involved in ResearchApplications for Summer Computer Science Research Internships (CURIS) at Stanford open on Sunday January 24th CURIS is the Computer Science departmentrsquos undergraduate research program Stanford students work with PhD students and a faculty member for the Summer with the goal of learning about and contributing to research Many internships produce an identifiable and publishable research result with students going on to top PhD programs Students who participate in CURIS open up opportunities in top-tier jobs graduate schools and often see their work shared and adopted worldwide

CURIS stipends are $5000-$9000 for 10 weeks The stipend level is set by the University following the guidelines on this page (go down to Dynamic Stipend Overview) httpsundergradstanfordeduopportunitiesresearchinformation-faculty-stafffaculty-department-grant-administration

Apply at httpcurisstanfordedu Applications are due by Sunday February 7 You rank the projects yoursquove applied to research groups rank the students who applied to their projects and CURIS matches students to projects using the Gale-Shapely bipartite matching algorithm

Projects hold office hours (over Zoom) during the application period so you can talk with the faculty and students on the project to introduce yourself and learn more Project listings should specify their office hours if they arenrsquot listed email the contact person

To help with your application the CURIS mentors are holding office hoursTuesdays 1-2pm - Book a slot at httpscalendlycomaabuhashcurisohTuesdays 4-5pm (drop-in) - Zoom Link

There will also be an information session with PhD students and prior CURIS participants which we will announce later this week

For any additional question please email curis-mentorscsstanfordedu

Apply for Internships

The Computer Forum will be holding their Winter Career Fair virtually on Career Fair Plus on January 27 from 1100am ndash 400pm This fair is only for Stanford students

Computer Forum Career Fair

Date Wednesday January 27

Time 1100am ndash 400pm PT

Student registration is now open and you can book your meetings with companies HERE

Here is a helpful article on how to prepare for the career fair

In addition you can read this article on how to book meeting on the web portal

lecturepop()

Queue

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

137 42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

42 271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

271 314

Queue

A Queue is a data structure representing a waiting line

Objects can be enqueued to the back of the line or dequeued from the front of the line

No other objects in the queue are visible Example A checkout counter

314

An Application Looper

Loopers

A looper is a device that records sound or music then plays it back over and over again (in a loop)

These things are way too much fun especially if yoursquore not a very good musician 128515

Letrsquos make a simple looper using a Queue

Building our Looper

Our looper will read data files like the one shown to the left

Each line consists of the name of a sound file to play along with how many milliseconds to play that sound for

Wersquoll store each line using the SoundClip type which is defined in our C++ file

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

G2wav 690G2wav 230Bb2wav 230G2wav 460G2wav 460G2wav 460G2wav 230Bb2wav 230G2wav 230F2wav 460

Building our Looper

Building our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1Clip 2 Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1

Clip 2

Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2Clip 3 Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

119135 119136119134

Building our Looper

Clip 1 Clip 2

Clip 3

Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Building our Looper

Clip 1 Clip 2 Clip 3Clip 4 Clip 5

front

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Enjoying Our Looper

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Feeling musical Want to contribute a loop for the next iteration of CS106B Send me your loop file and wersquoll add it

to our collection

Changing our Looper

Changing our Looper

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

QueueltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = loopdequeue() playSound(toPlayfilename toPlaylength)

loopenqueue(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Make a prediction ndash what are yougoing to hear when we use this

version of the looper

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5 119135 119136119134

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Changing our Looper

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

StackltSoundClipgt loop = loadLoop( hellip ) while (true) SoundClip toPlay = looppop() playSound(toPlayfilename toPlaylength)

looppush(toPlay)

Clip 1

Clip 1Clip 2

Clip 1Clip 3

Clip 4

Clip 5

Your Action Items

Read Chapter 52 and 53 These sections cover more about the Stack and Queue type and theyrsquore great resources to check out

Attend your first section How exciting

Finish Assignment 1 Read the style guide up on the course website for

more information about good programming style Review the Assignment Submission Checklist to

make sure your code is ready to submit

Next Time

Associative Containers Data sets arenrsquot always linear

Maps and Sets Two ways to organize information

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