#include #include using namespace std; class Foo; class Bar; class Foo { private: int foo; public: Foo(int n) { foo = n; } friend int bigger(Foo, Bar); }; class Bar { private: int bar; public: Bar(int n) { bar = n; } friend int bigger(Foo, Bar); }; int bigger(Foo a, Bar b) { return max(a.foo, b.bar); } int main() { Foo a(5); Bar b(55); cout << bigger(a, b); }