十一周任二

#include<iostream>#include<Cmath>using namespace std;class Point //定义坐标点类{public:    Point():x(0),y(0) {};    Point(double x0, double y0):x(x0), y(y0) {};    double getX()    {        return x;    }    double getY()    {        return y;    }    void PrintPoint(); //输出点的信息private:    double x,y;   //点的横坐标和纵坐标};void Point::PrintPoint(){    cout<<"Point:("<<x<<","<<y<<")";    //输出点}class Line: public Point   //利用坐标点类定义直线类, 其基类的数据成员表示直线的中点{public:    Line(Point pts, Point pte);  //构造函数，用初始化直线的两个端点及由基类数据成员描述的中点    double Length();    //计算并返回直线的长度    void PrintLine();   //输出直线的两个端点和直线长度private:    class Point pts,pte;   //直线的两个端点};//构造函数，分别用初始化直线的两个端点及由基类数据成员(属性)描述的中点Line::Line(Point pt1, Point pt2):Point((pt1.getX()+pt2.getX())/2,(pt1.getY()+pt2.getY())/2){    pts=pt1;    pte=pt2;}double Line::Length()  //计算并返回直线的长度{    double dx = pts.getX() - pte.getX();    double dy =pts.getY() - pte.getY();    return sqrt(dx*dx+dy*dy);}void Line::PrintLine(){    cout<<" 1st ";    pts.PrintPoint();    cout<<"\n 2nd ";    pte.PrintPoint();    cout<<"\n The Length of Line: "<<Length()<<endl;}int main(){    Point ps(-2,5),pe(7,9);    Line l(ps,pe);    l.PrintLine();//输出直线l的信息    cout<<"\n The middle point of Line: ";    l.PrintPoint() ;//输出直线l中点的信息    return 0;}