Nested Classes

NESTED CLASSES:

^Ø A class that contains the definition of another class called nesting class and the class inside the nesting class called nested class.

^Ø   The nesting class can access the data member and function member of a nested class. 

^Ø   Nested classes can directly use names, type names, names of static members, and enumerators only from the enclosing class. To use names of other class members, you must use pointers, references, or object names.

^Ø   The nesting of classes enables building of powerful data structures.

Syntax

class Nesting_Class

{

Public:

Data Members of Nesting Class;

class Nested_Class

{

public:

Data Member of Nested Class

Function Members of Nested Class

};

};

void main()

{

Nesting_class::Nested_class Object;

object.Nested_class Datamember=value;

object.Nested_class Functionmember();

}

Example:

#include<iostream.h>

#include<conio.h>

class fxclg //Nesting Class

{

public:

class cse   //Nested Class

{

public:

char name[10],dept[5];

int age;

void get()

{

cout<<"Enter Details Name Age Dept:\n";

cin>>name;

cin>>age;

cin>>dept;

cout<<"\n";

}

void put()

{

cout<<"name\t"<<name<<"age:\t"<<age<<"dept:\t"<<dept;

}

};

};

void main()

{

clrscr();

fxclg::cse cs1; //Declaring Object for Nested Class cs1.get();

cs1.put();

getch();

}

Output:

Enter Details Name Age Dept:

kumar

24

CSE

name kumar age:   24 dept: CSE

In this example, the class cse (nested class) is defined within the class fxclg(nesting class),To declare the objects of a nested class we have to follow the procedure, fxclg::cse c1; Using this object it access the data and function member of nested class cse