Oop In C++

IN THE NAME OF GOD

OOP C++

in

Maysam Rajaati

Farid Bekran

11/27/2008 Tabriz University - Iran

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TABLE OF CONTENTS 1. History 2. Philosophy of C++ & increments of C 3. Classes in C++ 4. Objects in C++ 5. Access Specifiers 6. Class & Object memory allocation 7. Static data (In classes) 8. Inheritance(Single) 9. Inheritance(multiple) 10.INCLUSIVE CLASSES 11.POLYMORPHISM 12.COMPILERS

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HISTORY  It was developed by Bjarne Stroustrup in1979 at Bell Labs.  As an enhancement to the C programming language and originally named "C with Classes".  It was renamed to C++ in 1983.

C

Simula

ADA83

Algol68

SmallTalk

CLU

ML

C++

C#

JAVA

ADA95

PHP

Perl

D

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PHILOSOPHY OF C++ & INCREMENTS OF C

 C++ is designed to be a statically typed general-purpose language that is as efficient and portable as C  C++ is designed to directly and comprehensively support multiple programming styles (procedural programming, data abstraction, object-oriented programming, and generic programming)  C++ avoids features that are platform specific or not general purpose

class

Virtual functions

Multiple inheritance

Templates

Operator overloading

C Exception handling

C+ + 4

CLASSES IN C++  Classes are User defined types.  Classes are for Encapsulate our data.  Classes hold both data and function on data. CPolygon class CPolygon { private: int Width; int Height; // You can remove “private” public: Cpolygon() // Has no return value { } int Area() { } void Draw() { } ~Cpolygon() // Has no Parameter , Has no return value { } };

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OBJECTS IN C++

Objects of Class

Definition of class Some Data

Some Data

Some Data

1000

10230

 Definition of a class only is the class Specification.  Object of a class allocate real memory for members. Example: … Cpolygon obj1; // call the user defined constructor Obj1.Draw(); // draw the obj1 to screen cout << Obj1.Area(); //prints the area of polygon obj1 // if scope ends the destructor called …

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ACCESS SPECIFIERS Class Cpolygon private

public

Cpolygon objB

NOT ALLOWED

protected

Example 1 : … Cpolygon obj1; cout << Obj1.Width; // ERROR! obj.Draw(); //True! …

Exam ple 2 : … class CPolygon { void Draw() { cout << Width << Height; // True } …

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CLASS & OBJECT MEMORY ALLOCATION Object 1

Object 2

Object 3

Data 1

Data 1

Data 1

Data 2

Data 2

Data 2

Function 1

Function 2

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STATIC DATAS(IN CLASSE) Object 2

Object 1

Static members use the access Secifiers of other members.

Object 3

Normal data

Normal data

Data 1

Data 1

Data 1

Data 2

Data 2

Data 2

Class A { … //public Static int x;//declaration … }; int A::x = 0;//definition Main() { cout << A::x; // access to static member … }

Normal data

Static data Data 3 Data 4

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STRUCTURES & CLASSES Difference between class and struct  Structure members are by default public but in class members are by default private.  Structures inherited publicly by default but classes inherited privately.

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INHERITANCE

A Single Inheritance

B

Multiple inheritance

C

B

C A

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INHERITANCE(SINGLE) Base Class

Feature B

Arrow means Derived from

class CPolygon { protected : int Wedth; int Height; public: int Area() { } int Draw() { } }; class CRectangle : public CPolygon { };

Feature D

Defined in Derived Class

Feature C

Feature C

Defined in Base Class

Feature A

Feature A

Feature B

Derived Class

CPolygon

CRectangle

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INHERITANCE(SINGLE) Access Specifier Base class has no access to derived class Class Derived private

Class Base

private protected

public

protected Base objB public

Derived objD

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INHERITANCE(SINGLE) Constructors of derived class

If derived class has no constructor compiler use suitable constructor of Base class.

Class Cpolygon { protected : int Width; int Height; public: Cpolygon(int para1 , int para2) : Width(para1), Height(para2) { } }; Class CRectangle: public Cpolygon { int ColorNmber; public: Crectangle(int para1 , int para2, int para3) :Cpolygon(para1, para2),ColorNumber(para3) { } }

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INHERITANCE(SINGLE) Public & Private Inheritance

class A private

protected

Class B : public A

Class C: private A

public

protected

A objA

NOT ALLOWED

private

public

B objB

private

protected

public

Public & Private Inheritance are methods that control Objects accessibility to parent public members.

C objC

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INHERITANCE(SINGLE) Overloading functions in base and derived class Class Cpolygon { … public: void Draw() { cout << “Drawing Cpolygon”<< “\n”;} }; Class CRectangle : public Cpolygon { … public: void Draw() { // use the suitable draw steps } }

Inplemention … CRectangle objREC; Cpolygon objPOL; objREC.Draw(); objPOL.Draw(); …

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INHERITANCE(MULTIPLE) Base class B

Base class A

Derived class C

class A { }; class B { }; class C : public A , public B { };

Overloading functions in this kind of inheritance is like single inheritance.

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INHERITANCE(MULTIPLE) Ambiguity class A { public: void show() { cout << “in A class”;}; }; class B { public: void show() { cout << “in B class”;}; }; class C : public A , public B { // this class has no method with show() signature }; Implementation : … C object; object.show(); // compile error Object.A::show(); // True Object.B::show(); // True …

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INCLUSIVE CLASSES Class Bird Class Wing Class Wing

Class Hen Class Wing

class wing { }; class bird { … wing obj; //bird has wing … }; class hen : public bird { }; // hen derived from bird

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POLYMORPHISM Polymorphism

Dynamic  Uses virtual function members  Run-time class Cpolygon { … virtual void Draw() { } … }

Cpolygon* ptrs[100]; … // fill the ptrs[100] for(int i=0 ; i<100 ; i++) ptrs[i] -> draw();

Static  Uses function overloading  Compile time

If you don’t use virtual keyword on base class function, call line of “for” statement will call the base class function in every step.

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COMPILERS  Dev C++ (open source) - Free  Microsoft Visual studio 2003 / 2005 / 2008 / 2010 - commercial  Borland C++ builder - commercial  Borland Turbo C++ explorer 2006 (Japanese , French , English ) - Free  Apple C++  IBM C++  Intel C++ for Linux  Sun Studio

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REFERENCES

• Lefor, Robert W. Object Oreinted Programming in C++, 3rd ed. • pratt, terans w. Programming language. • www.wikipedia.com • www.cplusplus.com

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