Gearing up for the stretch runCSCI 21, Spring 2013

Some tips

Search for answers on Google

Watch YouTube videos

Find a student or students in the class who are doing well and put together a study group

Do not leave lab hours when you finish your programming challenge – stay around and get help on your projects

Take advantage of the instructor’s office hours and email (priority email answers are given to those who attend ALL of our lecture and lab meeting hours)

Some tips (cont.)

Read the book before coming to class be prepared to ask questions in class

Attempt the programming challenge before coming to class be prepared to ask questions in class

We all know this is a very difficult class, and it requires a lot of hard work on your part – unfortunately, there is no easier way to learn this stuff minimum (‘C’ effort) time spent each week outside of

class: 6 hours

More tips

Read each project carefully as soon as it is posted – ask for clarification in lecture, lab,by email, or in office hours when needed

Start your project early (as soon as it is posted)

Try and keep your code in a compiling state constantly

Strive to do more than the bare minimum – ‘C’ students do the bare minimum

Makefile

always named Makefile not makefile, or makefile.txt, or anything else

always do the following have a target to link the executable have a target to compile each class separately have a target to compile the driver separately have a target to clean (rm/del *.o) have a target to cleanall (rm/del *.o and .exe)

Makefile (cont.)

What does a Makefile do? runs a series of compiler/linker commands for you

make allows you to specify a single target and only run

that single command make target

What is a target? one compiler or linker command

Makefile (cont.)

example: a program that only has a single source file

source file: myprogram.cpp

Makefile:

myprogram.exe: myprogram.og++ -o myprogram.exe myprogram.o

myprogram.o: myprogram.cppg++ -c myprogram.cpp

Makefile (cont.)

example: a program that only has a single source file make

executes the topmost target and all of its dependencies

typing make on the Makefile on the last slide would cause the following to happen: topmost target: myprogram.exe (executes second) dependency: myprogram.o (executes first) result: if no compiler/linker errors, will create

myprogram.o and then myprogram.exe

Makefile (cont.)

example: a program that only has a single source file make myprogram.o

only executes the command associated with the target myprogram.o

Makefile (cont.)

example: a program that has several source files

source file: myprogram.cpp, myclass.cpp, myhelper.cpp, myclass.h, myhelper.h

Makefile:

myprogram.exe: myprogram.o myclass.o myhelper.og++ -o myprogram.exe myprogram.o myclass.o myhelper.o

myprogram.o: myprogram.cppg++ -c myprogram.cpp

myclass.o: myclass.cppg++ -c myclass.cpp

myhelper.o: myhelper.cppg++ -c myhelper.cpp

Makefile (cont.)

example: a program that has several source files now you can type any of the following make

commands: make (topmost target and all of its dependencies) make myprogram.o make myclass.o make myhelper.o

Makefile (cont.)

add clean and cleanall targets to your Makefile

Windows

clean:cmd /C del *.o

cleanall: cleancmd /C del myprogram.exe

Makefile (cont.)

add clean and cleanall targets to your Makefile

Mac/Linux

clean:rm –f *.o

cleanall: cleanrm -f myprogram.exe

Makefile -- exercise

Create a Makefile to compile the following source files and build an executable that links them all together: executable: project3.exe source files:

project3.cpp DLNode.cpp, DLNode.h DLList.cpp, DLList.h

clean and cleanall targets

Project 3

Hopefully you have read the Project 3 specs, which were posted on Wednesday evening, March 27

The spec is complex, so will require your careful attention

Questions or any points of clarification?

Project 3 – getting started

How do I start Project 3 when I do not know how to code a linked list? First Iteration

stub out the classes and driver create a Makefile make

Second Iteration stub out the functions in the DLNode class make

Project 3 – getting started (cont.)

Third Iteration stub out the functions in the DLList class make

Fourth Iteration and on… implement a function in DLNode or DLList (complete

DLNode before moving on to DLList) make implement a test of the function in your driver make run the executable to view the test output

Project 3 – getting started (cont.)

Final Iterations after all of the functions have been implemented and

tested, clear out your driver and begin implementing the driver as needed for the final project

do it in steps – one small part of the driver functionality, make, run executable

When you think you have everything in place test with many, many input files – do your best to

break your program before you have to submit it

Linked lists

What is a linked list? a data structure

what is a data structure? a dynamic data structure

grows and shrinks as you add/remove data dynamic: think dynamic memory dynamic memory: think pointers

built by linking nodes

Linked lists (cont.)

What is a node? a container for a piece of data and one or more links

(pointers) to other nodes linked lists are built dynamically by creating nodes,

storing the desired data in the nodes, and then linking the nodes together

Linked lists (cont.)

Note how the nodes are linked together – this is a linked list

Conceptually, a node looks like this

Linked lists (cont.)

What does a node look like in code?class Node{

private:

// data type depends on what you //want to store in your listint data;

// link to next nodeNode* next;

};

Linked lists (cont.)

This picture looks like a bunch of nodes – where is the list?

The linked list is just the algorithms that are used to add, retrieve, update, and delete the nodes, plus some tracking sentinels that keep track of where the first node is – see Start above?