如何使asignment操作符重载工作以进行连续分配

Question

今天我接受了采访.我被要求编写一个使赋值运算符重载.

假设我有3个对象,例如

className obj1, obj2, obj3;

现在我想这样分配

obj1 = obj2 = obj3;

怎么做？

我在下面编写了一个程序,但它正在抛出错误 error: no match for ‘operator=’ in ‘ab = ab1.overload::operator=((* & ab2))’

#include <iostream>

using namespace std;
class overload{
public:
    int x, y;
    overload operator=(overload &);
    overload(){x = 1; y = 2;}
};
overload overload::operator=(overload &ov)
{
    overload o;
    o.x = ov.x;
    o.y = ov.y;
    cout << o.x << "..." << o.y << endl;
return o;
}
int main()
{
    overload ab, ab1, ab2;
    ab = ab1 = ab2;
return 0;
}

Answer 1

您正在修改本地对象并按值返回它.您需要修改this对象并返回对它的引用:

overload& overload::operator=(const overload& ov)
{
    this->x = ov.x;
    this->y = ov.y;
    return *this;
}

您得到的错误是因为函数返回的临时函数无法绑定到对非const的引用(因此const在我的示例中).