点派生类直线

#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) {};    void PrintPoint(); //输出点的信息    double getx()    {        return x;    }    double gety()    {        return y;    }protected:    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，从Point类继承的数据成员表示直线的中点};Line::Line(Point pt1, Point pt2):Point((pt1.getx()+pt2.getx())/2,(pt1.gety()+pt2.gety())/2){    pts=pt1;    pte=pt2;}double Line::Length(){    double a,b,c;    a=pts.getx()-pte.getx();    b=pts.gety()-pte.gety();    c=sqrt(a*a+b*b);    return c;    } void Line::PrintLine() {     cout<<"第一个点的端点为:"<<'('<<pts.getx()<<','<<pts.gety()<<')'<<endl;     cout<<"第二个点的端点为:"<<'('<<pte.getx()<<','<<pte.gety()<<')'<<endl;     cout<<"直线的长度为："<<Length(); }int main(){    Point ps(-2,5),pe(7,9);    Line l(ps,pe);    cout<<"About the Line: "<<endl;    l.PrintLine();  //输出直线l的信息：两端点及长度    cout<<"The middle point of Line is: ";    l.PrintPoint(); //输出直线l中点的信息    return 0;}