//

// Created by light on 19-12-23.

//

#include <iostream>

#include <string>

#include <vector>

struct Test {

Test() {

// std::cout << "construct a Test object" << std::endl;

}

Test(const Test &) {

std::cout << "copy construct a Test object" << std::endl;

}

Test &operator=(const Test &t) {

std::cout << "copy assignment a Test object" << std::endl;

return *this;

}

Test(Test &&t) { std::cout << "move construct a Test object" << std::endl; }

Test &operator=(Test &&t) {

std::cout << "move assignment a Test object" << std::endl;

return *this;

}

~Test() {

// std::cout << "destruct a Test object" << std::endl;

}

};

Test getTest() {

// anonymous object

return Test();

}

Test getTestWithName() {

// named return value

Test temp;

return temp;

}

/**

* 1.copy

* construct本身在RVO和NRVO两种情况下被优化了，如果再加上move反而画蛇添足。

* 2.加入了move assignment后，默认是调用move assignment而不是copy

* assignment，可以将move assignment注释后测试。

* 3.对于RVO和NRVO来说，construction的情况编译器优化得比较好了，加入move语义主要是对于assignment有比较大影响

*/

int main() {

std::cout << "==== common case ====" << std::endl;

Test o1;

std::cout << "---- Test copy construct: " << std::endl;

Test o2(o1); // two ways for copy construct

Test o3 = o1;

std::cout << "---- Test move construct: " << std::endl;

Test o4(std::move(o3));

std::cout << "---- Test assignment: " << std::endl;

o2 = o1;

std::cout << "---- Test move assignment: " << std::endl;

Test o5;

o5 = std::move(o4);

std::cout << "\n==== test for rvo ===" << std::endl;

std::cout << "---- Test rvo for copy construct: " << std::endl;

Test obj11(getTest());

Test obj1 = getTest();

std::cout << "---- Test rvo for move construct: " << std::endl;

Test obj12(std::move(getTest()));

std::cout << "---- Test rvo for assignment: " << std::endl;

Test obj2;

obj2 = getTest();

std::cout << "---- Test rvo move assignment: " << std::endl;

Test obj5;

obj5 = std::move(getTest());

std::cout << "\n==== test for nrvo ===" << std::endl;

std::cout << "---- Test nrvo for copy construct: " << std::endl;

Test obj33(getTestWithName());

Test obj3 = getTestWithName();

std::cout << "---- Test nrvo for move construct: " << std::endl;

Test obj34(std::move(getTestWithName()));

std::cout << "---- Test nrvo for assignment: " << std::endl;

Test obj4;

obj4 = getTestWithName();

std::cout << "---- Test nrvo move assignment: " << std::endl;

Test obj6;

obj6 = std::move(getTestWithName());

return 0;

}