C++调用函数是如何返回临时对象的

请看如下代码

#include "stdafx.h"


#include<iostream>
using namespace std;


class INT {
friend ostream& operator<<(ostream&os,const INT&i);


public:
INT(int i) :m_i(i) {
cout << "对象创造" << endl;
}
INT(const INT&other) {
this->m_i = other.m_i;
cout << "拷贝构造  " << endl;
}
INT&operator=(const INT&other) {
this->m_i = other.m_i;