#include <iostream>
#include <typeinfo>

using namespace std;

template<typename T1, typename T2>
auto add(T1 l, T2 r) -> decltype(l + r){
    return l + r;
}

class C {};

class B {};

class A {
public:
    C operator+(const B& b) {
        C c;
        return c;
    }
};


int main() {
    // Using add()
    A a;
    B b;
    auto c = add(a, b);
    
    cout << typeid(a).name() << endl;
    cout << typeid(b).name() << endl;
    cout << typeid(c).name() << endl;
    cout << endl;
    
    // Doing the same thing but not on a function
    A a2;
    B b2;
    auto c2 = a2 + b2;
    
    cout << typeid(a2).name() << endl;
    cout << typeid(b2).name() << endl;
    cout << typeid(c2).name() << endl;
}