1 Today’s Objectives Announcements Quiz #1 on 8-Jun (Wednesday) – over C++ material in Ch. 1, 2, 3 Be sure to study math operators, assignment operators,

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Today’s ObjectivesToday’s Objectives

Announcements• Quiz #1 on 8-Jun (Wednesday) – over C++ material in Ch. 1, 2, 3

Be sure to study math operators, assignment operators, relational operators, logic operators, if statements, for loops, while loops, incrementing, and common errors

Quick review of some basic C++ (Ch. 1 and Ch. 2)• C++ style output and input• Escape sequences• Variables• Arithmetic operators, equality operators, and relational operators

Control structures (Ch. 4 and Ch. 5)• Control structures – if and else, while, for, switch• Stream manipulators• Assignment operators and logical operators• Increment and decrement operators

Intro to UML – Unified Modeling Language• Algorithms and pseudocode• UML diagrams• The Software Life Cycle

Bonus Lab

5-Jun-20065-Jun-2006

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Quick Review ofSome Basic C++Quick Review ofSome Basic C++

Some C++ Features in Chapters 1 and 2

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Simple Example from Last WeekSimple Example from Last Week

Page 42, Fig. 2.4 Comments

// Everything after it on the same line is a comment/* Everything in between is a comment */

int main(){} //All execution starts here C++ statements end with semicolons ; Preprocessor directive to include a C++ standard library

#include <iostream>

All C++ library elements are in the “std” namespaceusing namespace std;using std::cout;

Outputcout represents the standard output, usually the screen<< stream insertion operator, can be concatenatedcerr represents the standard error output, also usually the screen

Quick Review (Deitel)Quick Review (Deitel)

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Escape SequencesEscape Sequences

Page 40, Fig. 2.2

Special characters used in printing\n Newline

\t Tab

\\ Backslash

\" Double quote

Example:

cout << "\nEscape sequences begin with a \"\\\"\n";


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VariablesVariables

Declaring variables, page 1232, Append. C//Datatype followed by a variable name//Can also be initialized when declaredint n, m = 0; //Initializes m but not ndouble x = 0.0;bool done = false;char userSelection = 'X';int n(0); //Functional style of initialization

What will print? Do variables have to be initialized?#include <iostream>using namespace std;int main(){

int n;cout << "n = " << n << "\n";

}


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Second Example from Last WeekSecond Example from Last Week

Page 43, Fig. 2.5

Inputcin represents the standard input, usually the keyboard>> stream extraction operator

cin can be used to capture input from the keyboard up to the first whitespace (e.g., space or return)double quiz1;cout << "Enter your grade for Quiz 1: ";cin >> quiz1;cout << "You typed " << quiz1 << endl;

endl to output a newline and flush output buffer


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Arithmetic OperatorsArithmetic Operators

Arithmetic operators, page 48, fig. 2.9+ Addition- Subtraction* Multiplication/ Division% Modulus, result is the remainder

Integer divisionint a = 28, b = 5;cout << "a / b = " << (a / b) << endl; //What prints?cout << "a % b = " << (a % b) << endl; //What prints?

Precedence, page 49, fig. 2.10 and page 1228, Append. A• Parentheses, innermost first, then left to right• *, /, %, left to right• +, -, left to right• Example: cout << (2 * (5 * 5) + 3 * 5) + 7 << endl;


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Equality Operators andRelational Operators

Equality Operators andRelational Operators

Equality operators• equality operator == (don’t confuse with = )

x == y; //x is equal to y• operator !=

x != y; //x is not equal to y

Relational operators• operator <

x < y; //x is less than y• operator >

x > y; //x is greater than y• operator <=

x <= y; //x is less than or equal to y• operator >=

x >= y; //x is greater than or equal to y

Quick Review (Deitel, 51–54, Fig. 2.12)Quick Review (Deitel, 51–54, Fig. 2.12)

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Where’s the Error?Where’s the Error?

#include <iostream>using namespace std;int main(){ bool done = false; while( !done ){ cout << "Continue?(Y/N): "; char input = 'Y'; cin >> input; if( input = 'N' )

done = true; } cout << "Bye!\n";}


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Control StructuresControl Structures

C++ Features in Chapters 4 and 5

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C++ Control StructuresC++ Control Structures

Sequence – built-in Selection structures

• if• if/else• switch

Repetition structures• while• do/while• for

Control Structures (Deitel, 127–131)Control Structures (Deitel, 127–131)

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if/elseif/else

Used to select from different actions, based on whether a condition is true

if( courseScore >= 92.5 )courseGrade = "A";

else if( courseScore >= 89.5 )courseGrade = "A-";

elsecourseGrade = "B";


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if( courseScore >= 92.5 );

courseGrade = "A";

Control Structures (Deitel)Control Structures (Deitel)

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Counter-Controlled while LoopCounter-Controlled while Loop

A while loop repeats an action as long as a condition is true

In this example, a counter controls the number of iterations

int grade, total=0, gradeCounter=1;while( gradeCounter <= 10 ){cout << "Enter grade ";cin >> grade;total = total + grade;gradeCounter = gradeCounter + 1;

}

Control Structures (Deitel, 137–145, Fig. 4.9 on p. 142)Control Structures (Deitel, 137–145, Fig. 4.9 on p. 142)

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int grade, total=0, gradeCounter=1;while( gradeCounter <= 10 );{cout << "Enter grade ";cin >> grade;total = total + grade;gradeCounter = gradeCounter + 1;

}

Control Structures (Deitel)Control Structures (Deitel)

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Sentinel-Controlled while LoopSentinel-Controlled while Loop

A sentinel is a special value used to signal that looping should end – useful when the number of iterations is not known in advance

int main(){char selection;string input;bool done = false;while( !done ){

printMenu();cout << "Enter your selection (x to quit): ";cin >> input;selection = input[0];if( selection == 'x' )

done = true;}

}

Control Structures (Deitel, 145–153, Fig. 4.13 on p. 151)Control Structures (Deitel, 145–153, Fig. 4.13 on p. 151)

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Stream ManipulatorsStream Manipulators

Special elements that can be used to format output Can be used with the stream insertion operator << Include the following library: #include <iomanip>

//Fig. 4.13, page 151, line 86cout << "Average = " << setprecision(2) << fixed << average << endl;

• setprecision(2) – print two digits to the right of the decimal• fixed – always use fixed point notation, not scientific notation, and

always print any trailing zeroes• setw(16) – set the width for each field to 16 spaces• left – left-justify a field

Control Structures (Deitel, 155)Control Structures (Deitel, 155)

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Assignment OperatorsAssignment Operators

Operators for abbreviating assignment expressions

Examplesint a = 1, b = 1, c = 1;a += 2; //The same as: a = a + 2a += b; //a = a + bb -= 3; //b = b – 3c *= 4; //c = c * 4c *= c;

//What will be printed?cout << "c = " << c << endl;

Control Structures (Deitel, 161, Fig. 4.19)Control Structures (Deitel, 161, Fig. 4.19)

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Increment and Decrement OperatorsIncrement and Decrement Operators

Operators that add 1 or subtract 1 from a variable

Post-increment and post-decrementint a = 1, b = 1;a++; // a = a + 1b--; // b = b – 1

Pre-increment and pre-decrement++a; // a = a + 1--b; // b = b - 1

Control Structures (Deitel, 161–164, Fig. 4.20)Control Structures (Deitel, 161–164, Fig. 4.20)

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for Loopfor Loop

for( int i=0; i<10; ++i ){ cout << i << " ";}

Initialization – assigns the starting value and is executed once.

Condition – tested at the beginning of each loop, and the loop is executed only if it evaluates to true.

Expression – evaluated at the end of each loop

Block of statements executed in

the loop


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A block is needed only if multiple statements are executed in each loop.

for( int i=0; i<10; ++i ){ cout << i; cout << " ";}

for Loopfor Loop

If only one statement is executed in each loop, it’s not necessary to define a

block with { and }.

for( int i=0; i<10; ++i ) cout << i << " ";


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Changes to the Value of iChanges to the Value of i

for( int i=0; i<5; ++i ){ cout << i << " ";}

IterationValue of i

during the loopExpression at the end of the loop

First loop 0 (starting value) i = i + 1

Second loop 1 i = i + 1

Third loop 2 i = i + 1

Fourth loop 3 i = i + 1

Fifth loop 4 i = i + 1


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for Loop Guidelinefor Loop Guideline

Use a “for” loop when you already know how many times to repeat your code

for loops are usually used to step through a data structure with a known length, such as an array

const int SIZE = 5;int myArray[SIZE] = {0,0,0,0,0};for( int i=0; i<SIZE; ++i ) cout << myArray[i] << " ";


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Nested for LoopNested for Loop

int result = 0;for( int i=0; i<3; ++i ) for( int j=0; j<5; ++j ) result++;

i j result

0 0 1

0 1 2

0 2 3

0 3 4

0 4 5

1 0 6

1 1 7

1 2 8

1 3 9

1 4 10

2 0 11

2 1 12

2 2 13

2 3 14

2 4 15


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Nested Loop with Dependent VariableNested Loop with Dependent Variable

int result = 0;for( int i=0; i<3; ++i ) for( int j=i; j<5; ++j ) result++;

i j result

0 0 1

0 1 2

0 2 3

0 3 4

0 4 5

1 1 6

1 2 7

1 3 8

1 4 9

2 2 10

2 3 11

2 4 12


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How many iterations?How many iterations?

for( int i=0; i<10; ++i ) cout << i << " ";

for( int i=10; i>0; --i ) cout << i << " ";

int result = 0;for( int i=0; i<2; ++i ) for( int j=0; j<3; ++j ) result++;


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switch Structureswitch Structure

Can replace a complicated if/else structure

char selection;cin >> selection;switch( selection ){ case '1': myStore.viewCustomerList(); break; case 'x': case 'X': done = true; break; default: cout << "Incorrect input" << endl; break;}


This controlling expression is compared to each of the case labels

Execution continues at the case label that matches

The break causes execution to go to the next line following the switch

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Logical OperatorsLogical Operators

Logical AND – both conditions must be true&&

Logical OR – one or the other condition must be true||

Examples:

if( gender == 'F' && age > 64 )

seniorFemales++;

if( average >= 90 || finalExam >= 90 )

grade = 'A';


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Intro to UMLIntro to UML

A tool forobject-oriented analysis and design

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Software ProcessSoftware Process

Series of steps for software development Sometimes called a “method”

No standard software process• But it is important to use a process

Important for non-trivial programs

Advantages1. Repeatable procedure2. Remember all the things that need to be done3. Measurable progress

Intro to UML (Sommerville)Intro to UML (Sommerville)

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Steps in Software DevelopmentSteps in Software Development

Also known as the “Software Life Cycle”

Requirements gathering Analysis Program Design Coding Testing Operations

Intro to UML (Royce)Intro to UML (Royce)

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Analysis and DesignAnalysis and Design

Analysis • Determine what a program should do, but not how it should

do it• Build models, e.g. with UML or pseudocode algorithms

Program Design• Adjust the models to simplify implementation and improve

execution• Determine how the program should work

When it’s done with object-oriented programs, it’s called object-oriented analysis and design, or OOAD

Intro to UML (Royce)Intro to UML (Royce)

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Tools for Analysis and DesignTools for Analysis and Design

Pseudocode algorithms• Algorithm = A step-by-step procedure for performing a

task in a finite time• Pseudocode = structured, English-like statements that

describe the algorithm

UML• Unified Modeling Language• Graphical language used to model object-oriented

programs• Use case diagrams, class diagrams, sequence

diagrams, activity diagrams, etc.

Intro to UML (Deitel)Intro to UML (Deitel)

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Algorithm arrayMax(A,n):Input: An array A storing n >= 1 integers.Output: The maximum element in A.

currentMax = A[0]for i = 1 to n – 1 do if currentMax < A[i] then currentMax = A[i]return currentMax

Pseudocode example 1 (more code-like)

Pseudocode AlgorithmPseudocode AlgorithmIntro to UML (Deitel, 125–127; Goodrich)Intro to UML (Deitel, 125–127; Goodrich)

set currentMax to the first element in the input arrayfor each element in the array if currentMax < the new element then set currentMax to the new elementreturn currentMax

Pseudocode example 2 (more English-like)

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UMLUML

Graphical language – symbols used to create diagrams that model object-oriented programs

Intro to UML (Deitel)Intro to UML (Deitel)

Use casediagrams

Classdiagrams

Sequence diagrams

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Phase 1: Requirements GatheringPhase 1: Requirements Gathering

What are we making?• Consult the stakeholders• Read the assignment and ask the instructor

Goal• Problem statement• List of requirements

UML tool• Use case diagrams

Intro to UML (Eckel)Intro to UML (Eckel)

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Phase 2: Analysis and DesignPhase 2: Analysis and Design

How will we build it?• Come up with a design describing the classes

Goal• Object model• Functional model – describes the operations of

the objects

Tools• UML – class diagrams• Pseudocode for the functional model

Intro to UML (Eckel; Blaha)Intro to UML (Eckel; Blaha)

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Phase 3: Coding and TestingPhase 3: Coding and Testing

Build the first version• Start programming

Goal• Get something working• Keep it simple – small, simple classes

Testing• Create tests early – even before coding• Automate testing as much as possible so that

tests can be run every time the program changes


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IterationsIterations

Iteration = repetition You won’t get the whole project right the

first time Start with the core functionality – get it

working, then add more features with each iteration


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Case Study: Video Rental SystemPhase 1 – What are we making?

Case Study: Video Rental SystemPhase 1 – What are we making?

1. The store will rent movies as either VHS tapes or DVDs.

2. The store will also rent games.

3. Multiple copies of all the most popular movies will be stocked.

4. The store clerk will need to be able to look up a movie by its title in order to determine whether it’s available in the store.

5. The store owner will need to print a list of movie and game titles that are in stock when doing the inventory.

6. The store needs to keep track of its customers, and only the registered customers can rent items. The clerk must be able to determine which customer has checked out an item, and also how many items they have checked out.

7. After renting a movie or game, the customer must return it after three days.


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Phase 2 – How will we build it?Discover classes by finding the nouns

Phase 2 – How will we build it?Discover classes by finding the nouns









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Eliminate nouns that are: irrelevant, redundant, or used only as values

Eliminate nouns that are: irrelevant, redundant, or used only as values









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Remaining nouns establish the basic structure of the object model

Remaining nouns establish the basic structure of the object model

storemovie

VHS tape

DVD

game

list

customer

item


In UML, Classes are modeled as rectangles, which can be divided into three sections.

The class name is at the top. The data members are in the middle. Member functions are at the bottom.

RentalItem– title : string– copiesInStock : int– copiesAvailable : int

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Operations can be discoveredby creating use cases

Operations can be discoveredby creating use cases









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Consider how a user of the system will interact with it

Consider how a user of the system will interact with it




StoreEmployee

Check out itemto customer


StoreEmployee

Add an item

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Validate the use case diagram with the stakeholders

Validate the use case diagram with the stakeholders


StoreEmployee Check out item

to customer

Add an item

Check in itemfrom customer

View itemsby title

Search fora title

Search fora customerAdd a customer

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Express the use cases as algorithms describing the operations

Express the use cases as algorithms describing the operations

Algorithm checkOutItem( title )

for each item in inventory

if( item.title == title )

item.checkOut()


StoreEmployee

Check out itemto customer

RentalItem– title : string– copiesInStock : int– copiesAvailable : int

+ checkOut()

Store

+ checkOutItem()

Then add the operations to the appropriate class.

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Bonus Lab #1Bonus Lab #1

Optional Procedure

• First, a demo by the instructor• Then you will complete the assignment on your own• Print it and hand it in before the end of class

Rules• Do your own work, but you may help each other• You may ask the instructor for help• You may leave if you finish early or if you do not wish to do this

assignment

1 bonus point added to a quiz grade for each correctly completed lab handed in before the end of class

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ReferencesReferences

Blaha, M., Premerlani W., Object-Oriented Modeling and Design for Database Applications. Upper Saddle River, NJ: Prentice Hall, 1998.

Deitel, H. M., and P. J. Deitel, C++ How to Program, Fourth Edition. Upper Saddle River, NJ: Prentice Hall, 2003.

Eckel, B., Thinking in C++, Second Edition. Upper Saddle River, NJ: Prentice Hall, 2002.

Goodrich, M. T., R. Tamassia, and D. Mount, Data Structures and Algorithms in C++. Hoboken, NJ: John Wiley & Sons, Inc., 2004.

Josuttis, Nicolai M., The C++ Standard Library, A Tutorial and Reference. Boston: Addison-Wesley, 1999.

Royce, W., Software Project Management. Boston: Addison-Wesley, 1998.

Sommerville, I. ,Software Engineering. Harlow, England: Addison-Wesley, 2001.

Documents

1 Today’s Objectives Announcements Quiz #1 on 8-Jun (Wednesday) – over C++ material in Ch. 1, 2, 3 Be sure to study math operators, assignment operators,