C++之我是二代我继承——点线

来源：互联网发布：js arguments foreach 编辑：程序博客网时间：2024/05/16 19:31
#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 get_x();    double get_y();//靠这两个函数读取protected中的x、y的值    void PrintPoint(); //输出点的信息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 p1, Point p2); //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};double Point::get_x(){    return x;}double Point::get_y(){    return y;}Line::Line(Point p1, Point p2):Point((p1.get_x()+p2.get_x())/2,(p1.get_y()+p2.get_y())/2){    pts=p1;    pte=p2;}double Line::Length(){    return sqrt((pts.get_x()-pte.get_x())*(pts.get_x()-pte.get_x())+(pts.get_y()-pte.get_y())*(pts.get_y()-pte.get_y()));}void Line::PrintLine(){    cout<<" 1st ";    pts.PrintPoint();    cout<<endl<<" 2nd ";    pte.PrintPoint();    cout<<endl<<" The Length of Line: "<<Length()<<endl;}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;}
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