设有下面关于点Point类的定义，请在此基础上派生出一个矩形Rectangle类，用以描述矩形的左上角的顶点，并能够计算矩形的面积，并给出测试程序，测试程序里，定义矩形的对象，求出矩形的面积和矩形的位置（即左上顶点和右下顶点的坐标）。 class Point {public: Point(int a,int b){ x=a; y=b;} Point(){x=0;y=0;} int GetY(){return y;} int GetX(){return x;} void SetY(int b){ y=b;} void SetX(int a){ x=a;} private: int x; int y; };

以下是派生出的Rectangle类的定义和测试程序：

#include <iostream>

using namespace std;

class Point {
public:
    Point(int a, int b) { x = a; y = b; }
    Point() { x = 0; y = 0; }
    int GetY() { return y; }
    int GetX() { return x; }
    void SetY(int b) { y = b; }
    void SetX(int a) { x = a; }
private:
    int x;
    int y;
};

class Rectangle : public Point {
public:
    Rectangle(int a, int b, int w, int h) : Point(a, b) { width = w; height = h; }
    int GetWidth() { return width; }
    int GetHeight() { return height; }
    void SetWidth(int w) { width = w; }
    void SetHeight(int h) { height = h; }
    int GetArea() { return width * height; }
    Point GetBottomRight() { return Point(GetX() + width, GetY() + height); }
private:
    int width;
    int height;
};

int main() {
    Rectangle rect(0, 0, 5, 10);
    cout << "Rectangle area: " << rect.GetArea() << endl;
    cout << "Top-left point: (" << rect.GetX() << ", " << rect.GetY() << ")" << endl;
    Point bottomRight = rect.GetBottomRight();
    cout << "Bottom-right point: (" << bottomRight.GetX() << ", " << bottomRight.GetY() << ")" << endl;
    return 0;
}

输出结果为：

Rectangle area: 50
Top-left point: (0, 0)
Bottom-right point: (5, 10)

可以看出，Rectangle类正确地计算了矩形的面积，并且能够获取矩形的左上角和右下角的坐标。