Question

我有一个基类，我有4个派生类。当然我写了2个类，例如。我创建了矢量并用派生类的对象填充它，然后我想要按区域函数的矢量基础排序。我想使用运算符重载。

我定义了运算符重载但不完全！请帮我！谢谢......

class Shape
    {
    public:
       Shape() {}
       virtual void draw() = 0;
       virtual int area() = 0;
       virtual void perimeter() = 0;
       bool operator >(Shape * shape_one , Shape* shape_two )
       {
           return shape_one->area() > shape_two->area();
       }

    protected :
        double height;
        double width;

    };

class Squar : public Shape
{
public:
    Squar(int _width) {
      width = _width;
    }
    void draw(){}
    int area(){
        return width * width;
    }

    void perimeter(){}
    bool operator >(Squar * squar_one , Squar* squar_two )
    {
        return squar_one->area() > squar_two->area();
    }

};

class Triangle : public Shape
{
public:
    Triangle(int _width , int _height) {
        width  = _width;
        height = _height;
    }
    void draw(){}
    int area(){

        return (width * height) / 2;
    }
    void perimeter(){}
    bool operator >(Triangle * triangle_one , Triangle* triangle_two )
    {
        return triangle_one->area() > triangle_two->area();
    }
};

int main()
{    
    Shape *rect         = new Rectangular( 1 , 9);
    Shape *squar        = new Squar(5);

    QVector <Shape *> list;
    list.push_back(rect);
    list.push_back(squar);
retuurn 0;
}

Answer 1

我理解回答这个问题。

在基类中添加以下代码：

bool operator <( Shape *item )
   {
       return this->area() < item->area();
   }

并在main中添加以下代码：

std ::sort(list.begin() , list.end() ,[](Shape* ptr_l , Shape* ptr_r) { return *ptr_l < ptr_r;} );

这段代码是对的！：）

在c ++中对运算符重载的对象进行排序

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