Friend Function Example.

#include<iostream.h>
#include<conio.h>
class square
{
int no;
public:
void accept()
{
cout<<"Enter no for square:";
cin>>no;
}
friend void sq(square s);
};
void sq(square s)
{
int ans;
ans=s.no*s.no;
cout<<"Square="<<ans;
}
void main()
{
clrscr();
square s;
s.accept();
sq(s);
getch();
}
/*Output:
Enter no for square:4
Square=16 */