copy-and-move-assignment-operators-for-a-class

mov.cpp

#include <iostream>
using std::cout;
using std::endl;

class A {
public:
    A(int x): mem_(x){}
    A& operator=(const A& other) {
        cout << "copy assignment operator" << endl;
        mem_ = other.mem_;
    }   // `obja = objb;` & `objc = std::move(obja);` both work

    A& operator=(A&& other) {
        cout << "move assignment operator" << endl;
        mem_ = other.mem_;
        other.mem_ = 99;
    }   // only `objc = std::move(obja);` work
private:
    int mem_;
};


int main() {
    A obja(1);
    A objb(2);
    A objc(3);

    obja = objb;
    objc = std::move(obja);

    return 0;
}