#include <iostream>

class A;

class B { 
    public: 
        B() {} 

        B(A &) { // conversion constructor that takes cv-unqualified A
            std::cout << "called B's conversion constructor" << std::endl; 
        } 
};

class A { 
    public: 
        operator B() const { // conversion operator that takes cv-qualified A
            std::cout << "called A's conversion …