友元函数求两点的距离

 

 

 

#include<iostream>
#include<cmath>
using namespace std;

class point
{

friend double get(point,point);
public:
    point(int a,int b)
    {
        x=a,y=b;
    }
private:
    int x,y;
};

double get(point a,point b)
{
    return sqrt(pow(a.x-b.x,2)+pow(a.y-b.y,2));
}
int main()
{
    int x1,y1,x2,y2;    
    cin>>x1>>y1>>x2>>y2;
    point p1(x1,y1),p2(x2,y2);
    cout<<get(p1,p2)<<endl;
    return 0;
}