C++创建一个名为Ellipse的椭圆类--练习

/*设计名为Ellipse的椭圆类*/
/*
其属性为外接矩形的左上角与右下角两个点的坐标，并能计算出椭圆的面积，并测试该类。
*/

#include<iostream>
#include<map>
#include<set>
#include<algorithm>
using namespace std;
const double PI = acos(-1.0);
class Point {
public:
    Point() {}
    Point(int a, int b) {
        setX(a);
        setY(b);
    }
    Point(Point &tp) {
        this->setX(tp.getX());
        this->setY(tp.getY());
    }
    Point get_Point()
    {
        cout << "Please enter the coordinate of another point[ 9 6 menas the point is(9,6) ]:";
        cin >> x >> y;
        return *this;
    }
    ~Point(){}
    void details() {
        cout << "The Point:"
            << "X-coordinate:" << x << endl
            << "Y-coordinate:" << y << endl;
    }
    int getX() {
        return x;
    }
    int getY() {
        return y;
    }
    void setX(int a) {
        x = a;
    }
    void setY(int b) {
        y = b;
    }
private:
    int x;
    int y;
};
class Ellipse {
public:
    Ellipse(int x1, int y1, int  x2, int y2) {
        Pa.setX(x1);
        Pa.setY(y1);
        Pb.setX(x2);
        Pb.setY(y2);
    }
    Ellipse(Point &a,Point &b) {    
        Pa = a;
        Pb = b;
    }
    Ellipse(){}
    ~Ellipse(){}
    double area() {
        double a = fabs(Pa.getX() - Pb.getX())*1.0;
        double b = fabs(Pa.getY() - Pb.getY())*1.0;
        return PI*a*b;
    }
    void show() {
        cout << "The area of the Ellipse is:"
            << area() << endl;
        cout << "The coordinates of the upper-left corner of its external rectangle and the two points in the lower-right corner are:" <<endl;
            Pa.details();
            Pb.details();
    }
private:
    Point Pa, Pb;
};
int main(void)
{
    Point a, b;
    a.get_Point();
    b.get_Point();
    Ellipse asp(a, b);
    asp.show();
    return 0;
}