我正在创建一个二维坐标类(名为“Point”)来帮助我学习 C++。我希望能够对 Point 类对象(例如 Point_a + Point_b)执行基本算术运算(+、-、*、/...)。但是，我也希望能够在 Points 和其他变量类型(int/float/double)之间执行此类操作。

这可以使用运算符/函数重载来完成。从我下面的代码(仅添加)可以看出，据我所知，我必须为每个附加变量类型包含两个附加函数，一个用于“Point + int/float/double”形式，一个用于“int/float/double + Point”形式。

#include <iostream>

using namespace std;

class Point
{
    private:
        double x, y;

    public:
        Point(double x_in, double y_in){
            setX(x_in);
            setY(y_in);
        }    
        // Getters and Setters omitted for brevity

        // --- Start of Addition Operator Overloads --- (Code Block A)

        friend Point operator+(const Point &p1, const Point &p2);   //Point + Point
        friend Point operator+(const Point &p1, int val);           //Point + Int
        friend Point operator+(int val, const Point &p1);           //Int + Point
        friend Point operator+(const Point &p1, float val);         //Point + Float
        friend Point operator+(float val, const Point &p1);         //Float + Point     
        friend Point operator+(const Point &p1, double val);        //Point + Double
        friend Point operator+(double val, const Point &p1);        //Double + Point

        // --- End of Addition Operator Overloads --- (Code Block A)
};

// --- Start of Addition Operator Overload Functions --- (Code Block B)

Point operator+(const Point &p1, const Point &p2){
    return Point(p1.x + p2.x, p1.y + p2.y);
}

Point operator+(const Point &p1, int val){
    return Point(p1.x + val, p1.y + val);
}

Point operator+(int val, const Point &p1){
    return Point(p1.x + val, p1.y + val);
}

Point operator+(const Point &p1, float val){
    return Point(p1.x + val, p1.y + val);
}

Point operator+(float val, const Point &p1){
    return Point(p1.x + val, p1.y + val);
}

Point operator+(const Point &p1, double val){
    return Point(p1.x + val, p1.y + val);
}

Point operator+(double val, const Point &p1){
    return Point(p1.x + val, p1.y + val);
}

    // --- End of Addition Operator Overload Functions --- (Code Block B)
int main()
{
    Point point_a( 2.00, 20.00);
    Point point_b( 0.50,  5.00);
    Point point_c = point_a + point_b;
    cout << "X = " << point_c.getX() << " and Y = " << point_c.getY() << endl;
    return 0;
}

似乎有很多重复，特别是在“Point + int/float/double”类型函数之间。我想知道是否有办法将其缩短一点。比方说，与其拥有整数、 float 和 double 的单独版本，不如拥有一个可以处理所有这三个版本的版本。例如将代码块“A”和“B”转换成如下内容:

    ...

    // --- Start of Addition Operator Overloads --- (Code Block A)

    friend Point operator+(const Point &p1, const Point &p2);           //Point + Point
    friend Point operator+(const Point &p1, int||float||double val);    //Point + Int/Float/Double
    friend Point operator+(int||float||double val, const Point &p1);    //Int/Float/Double + Point

    // --- End of Addition Operator Overloads --- (Code Block A)

    ...

...

// --- Start of Addition Operator Overload Functions --- (Code Block B)

Point operator+(const Point &p1, const Point &p2){
    return Point(p1.x + p2.x, p1.y + p2.y);
}

Point operator+(const Point &p1, int||float||double val){
    return Point(p1.x + val, p1.y + val);
}

Point operator+(int||float||double val, const Point &p1){
    return Point(p1.x + val, p1.y + val);
}

// --- End of Addition Operator Overload Functions --- (Code Block B)

...

上面的代码部分旨在表示所需的结果，而不是实际的功能(例如 int OR float OR double)。

简而言之，有什么方法可以让“friend Point operator+(const Point &p1, int val);”及其对应的函数(在代码块 B 中)接受整数、 float 和double 值，还是我需要为每种变量类型设置一个单独的值？

感谢您的宝贵时间。

最佳答案

其他答案提到模板，但实际上，所有数字类型都会自动提升为 double 。

因此，您只需提供Point和double方面的运算符即可。

#include <iostream>

using namespace std;

class Point
{
    private:
        double x, y;

    public:
        Point(double x_in, double y_in){
            setX(x_in);
            setY(y_in);
        }    
        // Getters and Setters omitted for brevity

        double getX() const { return x; }
        double getY() const { return y; }

        void setX(double v) { x = v; }
        void setY(double v) { y = v; }

        // unary ops
        Point& operator+=(Point const& other)
        {
            x += other.x;
            y += other.y;
            return *this;
        }

        Point& operator+=(double v)
        {
            x += v;
            y += v;
            return *this;
        }

        // --- Start of Addition Operator Overloads --- (Code Block A)

        friend Point operator+(Point p1, const Point &p2)
        {
            p1 += p2;
            return p1;
        }

        friend Point operator+(Point p1, double val)
        {
            p1 += val;
            return p1;
        }

        friend Point operator+(double val, Point p1)
        {
            p1 += val;
            return p1;
        }
        // --- End of Addition Operator Overloads --- (Code Block A)
};


    // --- End of Addition Operator Overload Functions --- (Code Block B)
int main()
{
    Point point_a( 2.00, 20.00);
    Point point_b( 0.50,  5.00);
    Point point_c = point_a + point_b;
    point_c += 10;
    Point point_d = point_c + 10;
    Point point_e = point_d + 10.1;
    cout << "X = " << point_c.getX() << " and Y = " << point_c.getY() << endl;
    return 0;
}

关于c++ - 如何在 C++ 中同时为整数、 float 和 double 据类型重载运算符，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46697525/