操作重载*(左侧和右侧) [英] operation overloading * (both left side and right side)

问题描述

我有一个班级垫

class Mat
{
 ..
..
..
   friend Mat& operator*(Mat s1,int elem){
     s1.multiWith(elem);
     return s1;
}
};

现在它适用于米1*2但如何让它工作2*m1

now it will work for m1*2 but how to make it work with 2*m1

推荐答案

a*b 运算符应该返回一个新对象，而不是对 a 的引用.

a*b operator is supposed to return a new object, not a reference to a.

在类中声明 operator* 的正确语法是:

Correct syntax to declare an operator* within the class is:

class Mat
{
   ..
   ..
   ..
   Mat operator*(int elem){
        Mat res = *this;
        res.multiWith(elem);
        return res;
   }
};

那么，左参数的类型必然是当前类(这里:a*b的左参数必然是一个Mat实例).

Then, type of the left parameter is necessarily the current class (here: left parameter of a*b is necessarily a Mat instance).

现在如果你在类外声明运算符，你可以自由选择左右参数的任何类型:

Now if you declare the operators outside the class, you are free to choose any type for left and right parameters:

class Mat
{

};

Mat operator*(const Mat& left,int right){
     Mat res;
     // do res=left*elem
     return res;
}

Mat operator*(int left,const Mat& right){
     Mat res;
     // do res=left*right
     return res;
}

这篇关于操作重载*(左侧和右侧)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！