C++返回局部引用的问题

Question

我是新手，向各位大神请教一个问题：
用元素接收返回的局部引用，会出现内存错误，但用引用接收返回的局部引用，没有问题，是什么原因？谢谢各位大神解答

Answer 1

因为你定义了拷贝构造函数

 #include <stdio.h>
#include <iostream>
using namespace std;

class Teacher
{
public:
    Teacher(int a);
    Teacher(const Teacher &t2);
    Teacher& retT();
    Teacher(int a,int b);
    ~Teacher();
    int a;
    int b;
};

Teacher::Teacher(int a) {
this->a = a;
cout << "执行Teacher构造函数 \n a=" << this->a << endl;
}
Teacher::Teacher(int a,int b) {
this->a = a;
this->b = b;
cout << "执行Teacher构造函数 \n this->a=" << this->a << ";this->b=" << this->b<< endl;
}
Teacher::Teacher(const Teacher &t2) {
this->a = t2.a;
cout << "执行Teacher的copy函数 t2.a=" << t2.a << endl;
}
Teacher::~Teacher() {
cout << "执行Teacher析构函数 this->=" << this->a << endl;
}

Teacher& Teacher::retT() {
Teacher t1(120);
Teacher &t2 = t1;
return t2;
}
void main() {
Teacher t1(12);
Teacher &t2 = t1.retT();
//Teacher t2 = t1.retT();
cout << "main05中的t2.a=" << t2.a << endl;
}

这么写不会调用拷贝构造函数

执行Teacher构造函数
a=12
执行Teacher构造函数
a=120
执行Teacher析构函数 this->=120
main05中的t2.a=120
执行Teacher析构函数 this->=12
Press any key to continue

这是输出