CPP Slides All

BasicsMachine, software, and program design

Computer OrganizationCPU - central processing unit

Memory

Input devices

Output devices

CPU - central processing unit Where decisions are made, computations are

performed, and input/output requests are delegatedMemory

Stores information being processed by the CPU

Input devices Allows people to supply information to computers

Output devices Allows people to receive information from computers

Computer Organization

Memory

InputDevices

OutputDevices

CPUBrains of the computer

Arithmetic calculations are performed using the Arithmetic/Logical Unit or ALU

Control unit decodes and executes instructionsArithmetic operations are performed using binary number system

Control UnitThe fetch/execute cycle is the steps the CPU takes to execute an instructionPerforming the action specified by an instruction is known as executing the instructionThe program counter (PC) holds the memory address of the next instruction

Fetch the instruction towhich the PC points

Increment the PC

Execute the fetchedinstruction

Input and Output DevicesAccessories that allow computer to perform specific tasks

Receive information for processing Return the results of processing Store information

Accessories that allow computer to perform specific tasks

Common input and output devices Speakers Mouse Scanner Printer Joystick CD-ROM Keyboard Microphone DVD

Accessories that allow computer to perform specific tasks

Common input and output devices Speakers Mouse Scanner Printer Joystick CD-ROM Keyboard Microphone DVD

Some devices are capable of both input and output Floppy drive Hard drive Magnetic tape

MonitorDisplay device that operates like a television

Also known as CRT (cathode ray tube)Controlled by an output device called a graphics cardDisplayable area

Measured in dots per inch, dotsare often referred to aspixels (short for pictureelement)

Standard resolutionis 640 by 480

Many cards supportresolution of 1280 by1024 or better

Number of colors supported varies from 16 to billions

1280pixelsacrossscreen

1024pixelsdown

screen

Application software Programs designed to perform specific tasks that are

transparent to the user

System software Programs that support the execution and

development of other programs Two major types

Operating systems Translation systems

Software

Application SoftwareApplication software is the software that has made using computers indispensable and popular

Common application software Word processors Desktop publishing programs Spreadsheets Presentation managers Drawing programs

Application software is the software that has made using computers indispensable and popular

Common application software Word processors Desktop publishing programs Spreadsheets Presentation managers Drawing programs

Learning how to develop application software is our focus

Examples Windows®, UNIX®, Mac OS X®

Controls and manages the computing resources

Important services that an operating system provides File system

Directories, folders, files Commands that allow for manipulation of the file system

Sort, delete, copy Ability to perform input and output on a variety of

devices Management of the running systems

Operating System

Translation SystemSet of programs used to develop software

A key component of a translation system is a translator

Some types of translators Compiler

Converts from one language to another Linker

Combines resourcesExamples

Microsoft Visual C++®, CBuilder®, g++, Code Warrior®

Performs compilation, linking, and other activities.

Software Development Activities

Editing

Compiling

Linking with precompiled files Object files Library modules

Loading and executing

Viewing the behavior of the program

Software Development Cycle

Compile

Library routines

Other object files

Execute

Source Program

IDEsIntegrated Development Environments or IDEs

Supports the entire software development cycle E.g., MS Visual C++, Borland, Code Warrior

Provides all the capabilities for developing software Editor Compiler Linker Loader Debugger Viewer

Engineering SoftwareSoftware engineering

Area of computer science concerned with building large software systems

Challenge Tremendous advances in hardware have not been

accompanied by comparable advances in software

Complexity Trade-offSystem complexity tends to grow as the system becomes more user friendly

Complexity

Total SoftwareComplexity

User Simplicity

Software Engineering GoalsReliability

Understandability

Cost Effectiveness

Adaptability

Reusability

Reliability An unreliable life-critical system can be fatal

Understandability Future development is difficult if software is hard to

understandCost Effectiveness

Cost to develop and maintain should not exceed profitAdaptability

System that is adaptive is easier to alter and expandReusability

Improves reliability, maintainability, and profitability

Abstraction Extract the relevant properties while ignoring

inessentials

Encapsulation Hide and protect essential information through a

controlled interfaceModularity

Hierarchy

inessentials

Dividing an object into smaller modules so that it is easier to understand and manipulate

Hierarchy

inessentials

Dividing an object into smaller modules so that it is easier to understand and manipulate

Hierarchy Ranking or ordering of objects based on some

relationship between them

Software Engineering Principles

Abstraction

Encapsulation

Modularity

Hierarchy

inessentials

Encapsulation

Modularity

Hierarchy

Extract the relevant object properties while ignoring inessentials

Defines a view of the object

Example - car Car dealer views a car from selling features

standpoint Price, length of warranty, color, …

Mechanic views a car from systems maintenance standpoint Size of the oil filter, type of spark plugs, …

Abstraction

Price? Oil change?

EncapsulationSteps

Decompose an object into parts Hide and protect essential information Supply interface that allows information to be modified in a

controlled and useful manner

Internal representation can be changed without affecting other system parts

Example - car radio Interface consists of controls

and power and antenna connectors The details of how it works is hidden

To install and use a radio Do not need to know anything about the radio’s electronics

ModularityDividing an object into smaller pieces or modules so that the object is easier to understand and manipulate

Most complex systems are modular

Example - Automobile can be decomposed into subsystems

Cooling system Radiator ThermostatWater pump

Ignition system Battery Starter Spark plugs

HierarchyHierarchy

Ranking or ordering of objects based on some relationship between them

Help us understand complex systems Example - a company hierarchy helps employees

understand the company and their positions within it

For complex systems, a useful way of ordering similar abstractions is a taxonomy from least general to most general

Northern Timber Wolf Taxonomy

Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Caninae Genus Canis Species Canis lupus Subspecies Canis lupus occidentalis Northern Timber Wolf

OO Design and ProgrammingObject-oriented design and programming methodology supports good software engineering

Promotes thinking in a way that models the way we think and interact with the real world

Example - watching television The remote is a physical object with

properties Weight, size, can send message

to the television The television is also a physical object

with various properties

ObjectsAn object is almost anything with the following characteristics

Name Properties The ability to act upon receiving a message

Basic message types Directive to perform an action Request to change one of its properties

The individual digits of a binary number are referred to as bits Each bit represents a power of two

01011 = 0 • 24 + 1 • 23 + 0 • 22 + 1 • 21 + 1 • 20 = 11

00010 = 0 • 24 + 0 • 23 + 0 • 22 + 1 • 21 + 0 • 20 = 2

Binary Arithmetic

00010 + 01011 01101

Binaryaddition

2+ 11 13

Equivalentdecimaladdition

Binary Arithmetic

5× 3 15

Equivalent decimal multiplication

0101 × 0011 0101 0101 0000 0000 0001111

Binary multiplication

Two’s ComplementRepresentation for signed binary numbersLeading bit is a sign bit

Binary number with leading 0 is positive Binary number with leading 1 is negative

Magnitude of positive numbers is just the binary representationMagnitude of negative numbers is found by

Complement the bits Replace all the 1's with 0's, and all the 0's with 1's Add one to the complemented number

The carry in the most significant bit position is thrown away when performing arithmetic

Two’s ComplementPerforming two's complement on the decimal 7 to get -7

Using a five-bit representation

7 = 00111 Convert to binary

11000 Complement the bits

11000 Add 1 to the complement + 00001 11001 Result is -7 in two's complement

Two's Complement Arithmetic

Computing 8 - 7 using a two's complement representation with five-bit numbers

8 - 7 = 8 + (-7) = 1

01000 Two's complement of 8

11001 Two's complement of -7

01000 Add 8 and -7 + 11001 100001

00001 Is the five-bit result

Throw away the high-order

carry as we are using a five bit representation

Fundamentals of C++Basic programming elements and concepts

Program statement Definition Declaration Action

Executable unit Named set of program statements Different languages refer to executable units by

different names Subroutine: Fortran and Basic Procedure: Pascal Function : C++

Program Organization

Program OrganizationC++ program

Collection of definitions, declarations and functions Collection can span multiple files

Advantages Structured into small understandable units Complexity is reduced Overall program size decreases

ObjectObject is a representation of some information

Name Values or properties

Data members Ability to react to requests (messages)!!

Member functionsWhen an object receives a message, one of two actions are performed

Object is directed to perform an action Object changes one of its properties

// Program: Display greetings// Author(s): Ima Programmer// Date: 1/24/2001#include <iostream>#include <string>using namespace std;int main() { cout << "Hello world!" << endl; return 0;}

A First Program - Greeting.cppPreprocessor

directives

Insertionstatement

Ends executionsof main() which ends

program

Comments

Function

Function named main()

indicates start of

program

Provides simple access

Greeting Output

Definitions

Extraction

Definition with initialization

Area.cpp#include <iostream>using namespace std;int main() { // Extract length and width cout << "Rectangle dimensions: "; float Length; float Width; cin >> Length >> Width;

// Compute and insert the area

float Area = Length * Width;

cout << "Area = " << Area << " = Length " << Length << " * Width " << Width << endl; return 0;}

Visual C++ IDE with Area.cpp

Area.cpp Output

CommentsAllow prose or commentary to be included in programImportance

Programs are read far more often than they are written Programs need to be understood so that they can be

maintainedC++ has two conventions for comments

// single line comment (preferred) /* long comment */ (save for debugging)

Typical uses Identify program and who wrote it Record when program was written Add descriptions of modifications

Fundamental C++ ObjectsC++ has a large number of fundamental or built-in object typesThe fundamental object types fall into one of three categories

Integer objects Floating-point objects Character objects

11.28345

P 3.14

Integer Object TypesThe basic integer object type is int

The size of an int depends on the machine and the compiler On PCs it is normally 16 or 32 bits

Other integers object types short: typically uses less bits long: typically uses more bits

Different types allow programmers to use resources more efficientlyStandard arithmetic and relational operations are available for these types

Integer ConstantsInteger constants are positive or negative whole numbersInteger constant forms

Decimal Octal (base 8)

Digits 0, 1, 2, 3, 4, 5, 6, 7 Hexadecimal (base 16)

Digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a , b, c, d, e, f, A, B, C, D, E, F

Consider 31 oct and 25 dec

Decimal ConstantsExamples

97 40000L 50000 23a (illegal)

The type of the constant depends on its size, unless the type specifier is used

L or l indicates long integer

Character Object TypesCharacter type char is related to the integer typesCharacters are encoded using a scheme where an integer represents a particular characterASCII is the dominant encoding scheme

Examples ' ' encoded as 32 '+' encoded as 43 'A' encoded as 65 'Z' encoded as 90 'a' encoded as 97 'z' encoded as 122

Appendix A gives the complete ASCII character set

Character OperationsArithmetic and relational operations are defined for characters types

'a' < 'b' is true '4' > '3' is true '6' <= '2' is false

Character ConstantsExplicit (literal) characters within single quotes

'a','D','*'

Special characters - delineated by a backslash \ Two character sequences (escape codes) Some important special escape codes

\t denotes a tab \n denotes a new line \\ denotes a backslash \' denotes a single quote \" denotes a double quote

'\t' is the explicit tab character, '\n' is the explicit new line character, and so on

Literal String ConstantsA literal string constant is a sequence of zero or more characters enclosed in double quotes

"We are even loonier than you think" "Rust never sleeps\n" "Nilla is a Labrador Retriever"

Not a fundamental type

Floating-Point Object Types Floating-point object types represent real numbers

Integer part Fractional part

The number 108.1517 breaks down into the following parts 108 - integer part 1517 - fractional part

C++ provides three floating-point object types float double long double

Floating-Point ConstantsStandard decimal notation

134.1230.15F

Standard scientific notation1.45E6 0.979e-3L

When not specified, floating-point constants are of type double

F or f indicates single precision floating point value

L or l indicates long double floating point value

NamesUsed to denote program values or components

A valid name is a sequence of Letters (upper and lowercase) Digits

A name cannot start with a digit Underscores

A name should not normally start with an underscore

Names are case sensitive MyObject is a different name than MYOBJECT

There are two kinds of names Keywords Identifiers

KeywordsKeywords are words reserved as part of the language

int, return, float, double

They cannot be used by the programmer to name things

They consist of lowercase letters only

They have special meaning to the compiler

IdentifiersIdentifiers should be

Short enough to be reasonable to type (single word is norm) Standard abbreviations are fine (but only standard

abbreviations) Long enough to be understandable

When using multiple word identifiers capitalize the first letter of each word

Examples Min Temperature CameraAngle CurrentNbrPoints

DefinitionsAll objects that are used in a program must be defined

An object definition specifies Type Name

General definition form

Our convention is one definition per statement!

Type Id, Id, ..., Id;

Knowntype

List of one ormore identifiers

Exampleschar Response;int MinElement;float Score;float Temperature;int i;int n;char c;float x;

Objects are uninitialized with this definition form

(Value of a object is whatever is in itsassigned memory location)

Arithmetic OperatorsCommon

Addition + Subtraction - Multiplication * Division / Mod %

Note No exponentiation operator Single division operator Operators are overloaded to work with more than

one type of object

Write m*x + bnot mx + b

Integer DivisionInteger division produces an integer result

Truncates the result

Examples 3 / 2 evaluates to 1 4 / 6 evaluates to 0 10 / 3 evaluates to 3

ModProduces the remainder of the division

Examples 5 % 2 evaluates to 1 12 % 4 evaluates to 0 4 % 5 evaluates to 4

Operators and PrecedenceConsider mx + bConsider m*x + b which of the following is it equivalent to

(m * x) + b m * (x + b)

Operator precedence tells how to evaluate expressionsStandard precedence order

() Evaluate first, if nested innermost

done first * / % Evaluate second. If there are

several,then evaluate from left-to-

right + - Evaluate third. If there are

several,then evaluate from left-to-

Operator PrecedenceExamples

20 - 4 / 5 * 2 + 3 * 5 % 4

(4 / 5) ((4 / 5) * 2) ((4 / 5) * 2) (3 * 5) ((4 / 5) * 2) ((3 * 5) % 4)(20 -((4 / 5) * 2)) ((3 * 5) % 4)(20 -((4 / 5) * 2)) + ((3 * 5) % 4)

Defining and InitializingWhen an object is defined using the basic form, the memory allotted to it contains random information

Better idea to specify its desired value at the same time Exception is when the next statement is an

extraction for the object

Remember our convention of one definition per statement!

Examplesint FahrenheitFreezing = 32;char FinalGrade = 'A';cout << "Slope of line: ";float m;cin >> m;cout << "Intercept: ";float b;cin >> b;cout << "X value of interest: ";float x;cin >> x;float y = (m * x) + b;

Modifying ObjectsOperators and Expressions

Memory Depictionfloat y = 12.5;

12.5y1001100210031004

Memory Depictionfloat y = 12.5;int Temperature = 32;

Temperature

100110021003100410051006

Memory Depictionfloat y = 12.5;int Temperature = 32;char Letter = 'c';

TemperatureLetter

1001100210031004100510061007

Memory Depictionfloat y = 12.5;int Temperature = 32;char Letter = 'c';int Number;

TemperatureLetter

1001100210031004100510061007

-Number 10081009

Assignment StatementBasic form

object = expression ;Celsius = (Fahrenheit - 32) * 5 / 9;y = m * x + b;

Action Expression is evaluated Expression value stored in object

Target becomes source

Definitionint NewStudents = 6; 6NewStudents

Definitionint NewStudents = 6;int OldStudents = 21;

NewStudents

OldStudents

Definitionint NewStudents = 6;int OldStudents = 21;int TotalStudents;

NewStudents

OldStudents

-TotalStudents

Assignment Statementint NewStudents = 6;int OldStudents = 21;int TotalStudents;

TotalStudents = NewStudents + OldStudents;

NewStudents

OldStudents

?TotalStudents

NewStudents

OldStudents

27TotalStudents

OldStudents = TotalStudents;

NewStudents

OldStudents

27TotalStudents

OldStudents = TotalStudents;

NewStudents

OldStudents

27TotalStudents

Considerint Value1 = 10; 10Value1

Considerint Value1 = 10;int Value2 = 20;

Value1

Value2

Considerint Value1 = 10;int Value2 = 20;int Hold = Value1;

Value1

Value2

10Hold

Value1 = Value2;

Value1

Value2

10Hold

Value1 = Value2;

Value1

Value2

10Hold

Value1 = Value2;

Value2 = Hold;

Value1

Value2

10Hold

Value1 = Value2;

Value2 = Hold;

We swapped the values of objects Value1 and Value2 using Hold as temporary holder for Value1’s starting value!

Value1

Value2

10Hold

Incrementingint i = 1; i 1

Incrementingint i = 1;

i = i + 1;

Assign the value of expression i + 1 to i

Evaluates to 2

Const DefinitionsModifier const indicates that an object cannot be changed

Object is read-only

Useful when defining objects representing physical and mathematical constants

const float Pi = 3.1415;

Value has a name that can be used throughout the program

const int SampleSize = 100;

Makes changing the constant easy Only need to change the definition and recompile

Assignment ConversionsFloating-point expression assigned to an integer object is truncated

Integer expression assigned to a floating-point object is converted to a floating-point value

Considerfloat y = 2.7;int i = 15;int j = 10;i = y; // i is now 2cout << i << endl; y = j; // y is now 10.0cout << y << endl;

Nonfundamental TypesNonfundamental as they are additions to the languageC++ permits definition of new types and classes

A class is a special kind of typeClass objects typically have

Data members that represent attributes and values Member functions for object inspection and

manipulation Members are accessed using the selection operator

(.)j = s.size();

Auxiliary functions for other behaviorsLibraries often provide special-purpose types and classesProgrammers can also define their own types and classes

ExamplesStandard Template Library (STL) provides class string

EzWindows library provides several graphical types and classes

SimpleWindow is a class for creating and manipulating window objects

RectangleShape is a class for creating and manipulating rectangle objects

Class stringClass string

Used to represent a sequence of characters as a single object

Some definitionsstring Name = "Joanne";string DecimalPoint = ".";string empty = "";string copy = name;string Question = '?'; // illegal

Nonfundamental TypesTo access a library use a preprocessor directive to add its definitions to your program file

#include <string>The using statement makes syntax less clumsy

Without itstd::string s = "Sharp";std::string t = "Spiffy";

With itusing namespace std; // std contains stringstring s = "Sharp";string t = "Spiffy";

EzWindows Library ObjectsDefinitions are the same form as other objectsExample

SimpleWindow W;

Most non-fundamental classes have been created so that an object is automatically initialized to a sensible value

SimpleWindow objects have member functions to process messages to manipulate the objects

Most important member function is Open() which causes the object to be displayed on the screen Example

W.Open();

InitializationClass objects may have several attributes to initialize

Syntax for initializing an object with multiple attributesType Identifier(Exp1, Exp2, ..., Expn);

SimpleWindow object has several optional attributes

SimpleWindow W("Window Fun", 8, 4); First attribute

Window banner Second attribute

Width of window in centimeters Third attribute

Height of window in centimeters

An EzWindows Program#include <iostream>using namespace std;#include "ezwin.h"int ApiMain() {

SimpleWindow W("A Window", 12, 12);W.Open();

cout << "Enter a character to exit" << endl;char a;cin >> a;

return 0;}

An EzWindows Project File

Sample Display Behavior

RectangleShape ObjectsEzWindows also provides RectangleShape for manipulating rectangles

RectangleShape objects can specify the following attributes SimpleWindow object that contains the rectangle (mandatory) Offset from left edge of the SimpleWindow Offset from top edge of the SimpleWindow

Offsets are measured in centimeters from rectangle center Width in centimeters Height in centimeters Color

color is an EzWindows type

RectangleShape ObjectsExamplesSimpleWindow W1("My Window", 20, 20);SimpleWindow W2("My Other Window", 15, 10);

RectangleShape R(W1, 4, 2, Blue, 3, 2);RectangleShape S(W2, 5, 2, Red, 1, 1);RectangleShape T(W1, 3, 1, Black, 4, 5);RectangleShape U(W1, 4, 9);

RectangleShape ObjectsSome RectangleShape member functions for processing messages

Draw() Causes rectangle to be displayed in its associated

window GetWidth()

Returns width of object in centimeters GetHeight()

Returns height of object in centimeters SetSize()

Takes two attributes -- a width and height -- that are used to reset dimensions of the rectangle

Another EzWindows Program#include <iostream>using namespace std;#include "rect.h"int ApiMain() {

SimpleWindow W("Rectangular Fun", 12, 12);W.Open();RectangleShape R(W, 5.0, 2.5, Blue, 1, 2);R.Draw();cout << "Enter a character to exit" << endl;char Response;cin >> Response;return 0;

Sample Display Behavior

Compound AssignmentC++ has a large set of operators for applying an operation to an object and then storing the result back into the object

Examplesint i = 3;i += 4; // i is now 7cout << i << endl;

float a = 3.2;a *= 2.0; // a is now 6.4cout << a << endl;

Increment and DecrementC++ has special operators for incrementing or decrementing an object by oneExamplesint k = 4;++k; // k is 5k++; // k is 6cout << k << endl;int i = k++; // i is 6, k is 7cout << i << " " << k << endl;int j = ++k; // j is 8, k is 8cout << j << " " << k << endl;

Class stringSome string member functions

size() determines number of characters in the stringstring Saying = "Rambling with Gambling";cout << Saying.size() << endl; // 22

substr() determines a substring (Note first position has index 0)string Word = Saying.substr(9, 4); // with

find() computes the position of a subsequenceint j = Saying.find("it"); // 10int k = Saying.find("its"); // ?

Class stringAuxiliary functions and operators

getline() extracts the next input linestring Response;cout << "Enter text: ";getline(cin, Response, '\n');cout << "Response is \"" << Response << "\"” << endl;

Example runEnter text: Want what you doResponse is "Want what you do"

Class stringAuxiliary operators

+ string concatenationstring Part1 = "Me";string Part2 = " and ";string Part3 = "You";string All = Part1 + Part2 + Part3;

+= compound concatenation assignmentstring ThePlace = "Brooklyn";ThePlace += ", NY";

#include <iostream>using namespace std;int main() { cout << "Enter the date in American format: " << "(e.g., January 1, 2001) : "; string Date; getline(cin, Date, '\n'); int i = Date.find(" "); string Month = Date.substr(0, i); int k = Date.find(","); string Day = Date.substr(i + 1, k - i - 1); string Year = Date.substr(k + 2, Date.size() - 1); string NewDate = Day + " " + Month + " " + Year; cout << "Original date: " << Date << endl; cout << "Converted date: " << NewDate << endl; return 0;}

If Control ConstructA mechanism for deciding whether an action should be taken

Boolean AlgebraLogical expressions have the one of two values - true or false

A rectangle has three sides The instructor has a pleasant smile

The branch of mathematics is called Boolean algebra Developed by the British mathematician George Boole

in the 19th centuryThree key logical operators

And Or Not

Boolean AlgebraTruth tables

Lists all combinations of operand values and the result of the operation for each combination

ExampleP Q P and Q

False False FalseFalse True FalseTrue False FalseTrue True True

Boolean AlgebraOr truth table

P Q P or Q

False False FalseFalse True TrueTrue False TrueTrue True True

Boolean AlgebraNot truth table

P not P

False TrueTrue False

Boolean AlgebraCan create complex logical expressions by combining simple logical expressionsExample

not (P and Q)A truth table can be used to determine when a logical expression is true

P Q P and Q not (P and Q)

False False False TrueFalse True False TrueTrue False False TrueTrue True True False

A Boolean TypeC++ contains a type named boolType bool has two symbolic constants

true false

Boolean operators The and operator is && The or operator is || The not operator is !

Warning & and | are also operators so be careful what you

A Boolean TypeExample logical expressions

bool P = true;bool Q = false;bool R = true;bool S = (P && Q);bool T = ((!Q) || R);bool U = !(R && (!Q));

Relational OperatorsEquality operators

Examples int i = 32; int k = 45; bool q = (i == k); bool r = (i != k);

Relational OperatorsOrdering operators

< > >= <=

Examples int i = 5; int k = 12; bool p = (i < 10); bool q = (k > i); bool r = (i >= k); bool s = (k <= 12);

Operator Precedence Revisited

Precedence of operators (from highest to lowest) Parentheses Unary operators Multiplicative operators Additive operators Relational ordering Relational equality Logical and Logical or Assignment