小编non*_*ick的帖子

考虑以下 C++ 代码：

#include <bits/stdc++.h>

template <typename T> void print_type() { std::cout << __PRETTY_FUNCTION__ << std::endl; }

class Base{
    int num;
public:
    Base() : num{0} {}

    friend std::ostream & operator << ( std::ostream& stream, Base & obiekt){
        stream<< "num: " << obiekt.num;
        return stream;
    }
};

int main(){
    Base a{};
    std::cout << a << std::endl;
    std::cout << "type of a: " << std::endl;
    print_type < decltype( a ) > (); 

    std::cout << "type of (a): " << std::endl;
    print_type < …