Sample C++ program using Friend Function

#include<iostream>
using namespace std;
class complex
{


    float x;
    float y;
public:
    void input(float real, float img)
    {
              x = real;
              y = img;
     }

    friend complex sum(complex, complex);

    void show(complex);
};

complex sum(complex c1, complex c2)
{
    complex c3;
    c3.x = c1.x + c2.x;
    c3.y = c1.y + c2.y;
    return(c3);
}

void complex :: show(complex c)
{
    cout << c.x << " + j" << c.y << "\n";
}

int main()
{
    complex A, B, C;

    A.input(5.1, 5.25);
    B.input(9.95, 6.2);

    C = sum(A,B);

    cout << "A = "; A.show(A);
    cout << "B = "; B.show(B);
    cout << "C = "; C.show(C);

    return 0;
}

Output will be as