Friend Function Using C++

#include<iostream.h>

class Sample

{

int a;

int b;

public:

void setvalue()

{

a=25;

b=40;

}

friend int avg(Sample s);

};

int avg(Sample s)

{

return(s.a+s.b)/2;

}

Void main()

{

Sample x;

x.setvalue();

cout<<avg(x);

}

************************************

Friend function

With the use of a friend function we can access the private data of a class.

class Abc

{

….

….

public:

….

friend void xyz();/declaration

};

Characteristics of friend function

>It is not in the scope of the class to which it has been declared 

>Since it is not in the scope of the class,it cannot be called using the object of that class

>It can be invoked like a normal function without the help of any object

>But we cannot access the member names directly & has to use an object name & dot operator

 (e.g. A.x)

>Usually it has the objects as arguments