重载的“operator +”必须是一元或二元操作符错误 [英] overloaded 'operator+' must be a unary or binary operator error

问题描述

按照提供的建议这个回答，我重载了 + 操作符在我简单的 Point 类如下（+重载工作正常）。

Following the advice given in this answer, I have overloaded the + operator in my simple Point class as follows (the += overload works fine).

Point operator+ (Point p1, const Point& p2)
{
    return std::move(p1 += p2);
}

但我收到一个错误，说

重载的'operator +'必须是一元或二元运算符（有3个参数）

overloaded 'operator+' must be a unary or binary operator (has 3 parameters)

什么是错的？

推荐答案

听起来你已经声明你的操作符是一个成员函数。成员函数接受隐式第一个参数，这意味着您的运算符现在需要三个参数。

It sounds like you have declared your operator as a member function. A member function takes an implicit first parameter, meaning your operator now takes three parameters. You can fix this by making it a non-member function.

在任何情况下，最好声明为非成员 ，以确保LHS和操作的RHS之间的对称性。

In any case, it is preferable to declare it as a non-member, to ensure symmetry between the LHS and the RHS of the operation.

对于标题中的实用程序/移动> std :: move 。虽然我看不到在这里使用它的原因。

As for std::move, it is in the <utility> header. Although I can't see the reason to use it here.

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