A simple and complete C++ program to demonstrate global friend

#include <iostream>
class A
{
int a;
public:
A() {a = 0;}
friend void showA(A&); // global friend function
};
void showA(A& x) {
// Since showA() is a friend, it can access
// private members of A
std::cout << “A::a=” << x.a;
}
int main()
{
A a;
showA(a);
return 0;
}

Output:
A::a = 0