计算两点间距离

问题描述：计算两点间距离。

程序输出：距离

#include <iostream>

#include<math.h>

using namespace std;

class CPoint

{

private:

double x;

double y;

public:

CPoint(double xx=0,double yy=0):x(xx),y(yy) {}

double distance1(CPoint &);

friend double distance2(CPoint &, CPoint &) ;

double getX()

{

return x;

}

double getY()

{

return y;

}

};

double distance2(CPoint &p1, CPoint &p2);

double CPoint::distance1(CPoint &p)

{

double dx,dy;

dx=x-p.x;

dy=y-p.y;

return sqrt(dx*dx+dy*dy);

}

double distance2(CPoint &p1, CPoint &p2)

{

double dx,dy;

dx=p1.x-p2.x;

dy=p1.y-p2.y;

return sqrt(dx*dx+dy*dy);

}

double distance3(CPoint &p1, CPoint &p2)

{

double dx,dy;

dx=p1.getX()-p2.getX();

dy=p1.getY()-p2.getY();

return sqrt(dx*dx+dy*dy);

}

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;

return 0;

}