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。为两个a = b;对象分配foo时会发生什么？ 选项是：

1. 使用自动赋值运算符
2. 复制构造函数

Answer 1

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