C++ program to use friend class

#include<iostream>
#include<conio.h>

class one
{
    private:
        int i;
    public:
        one()
        {
            i = 10;
        }
    friend class two;
};

class two
{
    public:
        fun(one a)
        {
            std::cout<<a.i<<std::endl;
        }
};

int main()
{
    system("cls");
    one a;
    two b;
    b.fun(a);

    getch();
    return 0;
}

10