c++ - 如果未定义赋值运算符，是否调用复制构造函数？

Question

假设 foo 类没有重载的赋值运算符。当为两个 foo 对象赋值 a = b; 时会发生什么？选项是:

1. 使用了自动赋值运算符
2. 拷贝构造函数

Answer 1

这取决于:

A a;
//this is not an assignment, it is equivalent to A b(a);
A b = a; //default copy constructor is called

A c;
//assignment
c = a; //default assignment operator is called