计算两点之间的距离。将两点之间距离函数声明为Point类的友元函数。#include<iostream.h>#include<math.h>class Point{ public:Point() {x=a; y=b; }int xcord() { return x;}int ycord (){ return y;}private:int x,y;(Point p1,Point p2);};(Point p1,Point p2){ double dx=double(p1.x-p2.x);double dy=double(p1.y-p2.y);return sqrt(dx*dx dy*dy);}void main(){ Point q1(0,0),q2(1,1);cout<<"The distance is: "<<Distance(________<<endl;}