如何在 C++ 中重载一元减号运算符？
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How to overload unary minus operator in C++?
提问by Ilya Suzdalnitski
I'm implementing vector class and I need to get an opposite of some vector. Is it possible to define this method using operator overloading?
我正在实现向量类，我需要得到一些向量的对立面。是否可以使用运算符重载来定义此方法？
Here's what I mean:
这就是我的意思：
Vector2f vector1 = -vector2;
Here's what I want this operator to accomplish:
这是我希望此运算符完成的操作：
Vector2f& oppositeVector(const Vector2f &_vector)
{
x = -_vector.getX();
y = -_vector.getY();
return *this;
}
Thanks.
谢谢。
回答by
Yes, but you don't provide it with a parameter:
是的，但您没有为其提供参数：
class Vector {
...
Vector operator-() {
// your code here
}
};
Note that you should not return *this. The unary - operator needs to create a brand new Vector value, not change the thing it is applied to, so your code may want to look something like this:
请注意，您不应返回 *this。一元 - 运算符需要创建一个全新的 Vector 值，而不是更改它所应用的对象，因此您的代码可能需要如下所示：
class Vector {
...
Vector operator-() const {
Vector v;
v.x = -x;
v.y = -y;
return v;
}
};
回答by Alexander Gessler
It's
它是
Vector2f operator-(const Vector2f& in) {
return Vector2f(-in.x,-in.y);
}
Can be within the class, or outside. My sample is in namespace scope.
可以在班内，也可以在班外。我的示例在命名空间范围内。
