第十三周（项目三）——与圆心相连的直线。

来源：互联网发布：linux终端运行w3m 编辑：程序博客网时间：2024/05/12 20:25
/*02.*烟台大学计算机学院学生03.*All right reserved.04.*文件名称*烟台大学计算机学院学生05.*All right reserved.06.*文件名称:与圆心相连的直线07.*作者：王洪海08.*完成日期：2013年5月25日09.*版本号：v1.010.*对任务及求解方法的描述部分:与圆心相连的直线11.*我的程序：12.*/#include <iostream>#include <string>#include <cmath>using namespace std;class Circle;   //由于在Point中声明友元函数crossover_point中参数中用了Circle，需要提前声明class Point{ protected:   double x;   double y; public:   Point(double x0=0,double y0=0):x(x0),y(y0){}  ~Point(){}   double getx()   {       return x;   }   double gety()   {       return y;   }   friend ostream& operator <<(ostream &,Point &);   friend void crossover_point(Point &p,Circle &c, Point &p1,Point &p2 );};ostream& operator <<(ostream &output,Point &p){    output<<"("<<p.x<<","<<p.y<<")"<<endl;    return output;}class Circle:public Point{ protected:   double r; public:   Circle(double x0=0,double y0=0,double r0=0):    Point(x0,y0),r(r0){}   ~Circle(){}   friend ostream& operator <<(ostream &,Circle &);   friend void crossover_point(Point &p,Circle &c, Point &p1,Point &p2 );};ostream& operator <<(ostream &output,Circle &c){    output<<"圆心为：("<<c.x<<","<<c.y<<")  圆的半径为："<<c.r<<endl;    return output;}void crossover_point(Point &p,Circle &c, Point &p1,Point &p2 ){    p1.x = (c.x + sqrt(c.r*c.r/(1+((c.y-p.y)/(c.x-p.x))*((c.y-p.y)/(c.x-p.x)))));    p2.x = (c.x - sqrt(c.r*c.r/(1+((c.y-p.y)/(c.x-p.x))*((c.y-p.y)/(c.x-p.x)))));    p1.y = (p.y + (p1.x -p.x)*(c.y-p.y)/(c.x-p.x));    p2.y = (p.y + (p2.x -p.x)*(c.y-p.y)/(c.x-p.x));}int main( ){    Point p(1,1),p1,p2;    Circle c(3,2,4);    crossover_point(p,c,p1,p2);    cout<<"点p: "<<p<<endl;    cout<<"与圆c: "<<c<<endl;    cout<<"的圆心相连，与圆交于两点，分别是："<<endl;    cout<<"交点1: "<<p1<<endl;    cout<<"交点2: "<<p2<<endl;    return 0;}
运行结果，如下图：
0 0