项目2

#include<iostream>#include<cmath>using namespace std;class  CPoint{private:    double x;  // 横坐标    double y;  // 纵坐标 public:    CPoint(double xx=0,double yy=0):x(xx),y(yy){}    double distance1(CPoint &);    friend double distance2(CPoint &,CPoint &);    double get_x(){return x;}    double get_y(){return y;}};double distance3(CPoint &a,CPoint &b){ return sqrt(((a.get_x()-b.get_x())*(a.get_x()-b.get_x())+(a.get_y()-b.get_y())*(a.get_y()-b.get_y())));}double distance2(CPoint &a,CPoint &b){  return sqrt(((a.get_x()-b.get_x())*(a.get_x()-b.get_x())+(a.get_y()-b.get_y())*(a.get_y()-b.get_y())));}double CPoint::distance1(CPoint &b){return sqrt(((x-b.get_x())*(x-b.get_x())+(y-b.get_y())*(y-b.get_y())));}int main(){   CPoint p1(10,13), p2(-5,6);    cout<<"1. "<<p1.distance1(p2)<<endl;    cout<<"2. "<<distance2(p1,p2)<<endl;    cout<<"3. "<<distance3(p1,p2)<<endl;    //system("pause");    return 0;}

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