Need for Inheritance

Capability of inheriting features.

Transitive relationship.

Reusablity of class.

Presented By

Lakshmi Kumari

K.V. Shaktinagar

Content

• Introduction

• Different forms of inheritance

• Visibility mode

• Accessibility of base class member

• Assignment

INHERITANCE

The mechanism of deriving a new class from an old one is called Inheritance.

Raj

Father

Rani Roshan

Base Class

Derived Class

Existing class is called Base Class.

New class is called derived class.

INHERITANCE

SINGLE INHERITANCE MULTIPLE INHERITANCE

MULTILEVELINHERITANCE

HIERARCHICALINHERITANCE

HYBRID INHERITANCE

When a subclass inherit only from one base class,it is known as single inheritance.

Super Class

Derived Class

Super Class(Base Class)

Sub Class(Derived Class)

Syntax:

Class Derived-class : Mode base-class

{

St1;

St2;

};

Colon gives that derived class-name is derived from base-class.

Mode is either private or public.By default mode is private

Base Class & Derived Class

The new class is called Derived Class and old one is called Base class.

Class Student{ Public: int Roll;};

Class Ipstudent : public Student{ Private : int ipmarks; Public : void info( )

{ cout<< Roll; cout<<ipmarks; }

}; Main( )

{ ipstudent ip;

ip.Roll=1;

Ip.info( );

}

When many subclasses inherit from a single base class ,it is known as hierarchical inheritance.

Syntax:

Class Derived-class : Mode base-class1,Mode base-class2

{

St1;

St2;

};Mode is either private or public.By default mode is private

Name of different base class

Super Class

Sub Class 2

Sub Class 1

When a subclass inherits from a class that itself inherits from another class it is known as multilevel inheritance.Slide 6

When one subclass inheriting from many base class ,it is known as hierarchical inheritance.Syntax:

When a subclass inherits from multiple base classes and all of its base classes inherit from a single base class,this form of inheritance is known as hybrid inheritance..

Visibility Mode

• Private When base class is privately accessed by derived class then

• Public member Private

• Protected member Private

• Private member Not inherited

Base Class Derived Class

become

Visibility Mode

• Public When base class is publicly accessed by derived class then

• Private member Not inherited

• Public member Public

• Protected member Protected

Base Class Derived Class

Visibility Mode

• Protected When base class is accessed protectly by derived class then

• Private member Not inherited

• Public member Protected

• Protected member Protected

Base Class Derived Class

The significance of visibility modes

• Private :-When the derived class require to use some attributes of the base class and these inherited features are intended not to be inherited further .

• Public :-When the situation wants the derived class to have all the attributes of the base class,plus some extra attributes.

• Protected:- When the features are required to be hidden from the outside world and at same time required to be inheritable.

Accessibility of base class memberAccess Specifier Accessible from

own class Accessible from derived class(inheritable)

Accessible from object outside class

Public Yes Yes Yes

Protected Yes Yes No

Private Yes No No

Assignment

• What is inheritance?

• How many type of inheritance?

• When should one derive a class publicly or privately?

class PUBLISHER{

char Pub[12];double Turnover;

protected:void Register();

public:PUBLISHER();void Enter();void Display();

}; class BRANCH{

char CITY[20];protected:

float Employees;public:

BRANCH();void Haveit();void Giveit();

}; class AUTHOR:private BRANCH,public PUBLISHER{

int Acode; char Aname[20];

float Amount;public:

AUTHOR();void Start();void Show();

};

 1.Write the names of data members, which are accessible from objects belonging to class AUTHOR.2.Write the names of all the member functions which are accessible from objects belonging to class BRANCH.3. Write the names of all the members which are accessible from member functions of class AUTHOR.4 How many bytes will be required by an object belonging to class AUTHOR? 

May you all prosper and be happy! With a lot of love and respect

 Thank You all