Friend function in c++ (OOP) (13)

               //friend function

                                       //***************

/*friend function is declared in the class with friend keyword. it must be defind outside the class to which

it is a friend.friend function is not the member function of the class to which it is a friend.*/

#include<iostream>

using namespace std;

class A; //declare the first class

class B //defining the second class

{

private: //private part of the class

int b;

public: //public part of the class

void getval(int x)

{

b=x;

}

void putval()

{

cout<<"the value of b is:"<<b<<endl;

}

friend void add(A,B); //declare the friend function

};

class A //defining the first class

{

private: //private part of the class

int a;

public: //public part of the class

void getval(int x)

{

a=x;

}

void putval()

{

cout<<"the value of a is:"<<a<<endl;

}

friend void add(A,B); //declare the friend function

};

void add(A ob1,B ob2) //define the friend function outside the class

{

cout<<"the sum is:"<<ob1.a+ob2.b<<endl;

}

int main()

{

A a; // making object of first class

B b; //making object of second class

a.getval(100);

b.getval(200);

a.putval();

b.putval();

add(a,b); //passing object as a function 

}