求大神助攻，程序错误改不出啊

#include<iostream>
#include<math.h>
using namespace std;
class Point
{
private:
float x;
float y;
public:
//Ponit(){};
Point(float a=0,float b=0){x=a;y=b;cout<<"构造函数"<<endl};
Point(Point &){};
friend int distance(Point &p,Point &q);
};
int distance(Ponit &p,Point &q)
{return(sqrt((p.x-q.x)^2+(p.y-q.y)^2));
}
void main()
{
Point p1,p2(10.0,6.0);
Point p3=p2;
double d=int distance(p1,p2);
cout<<"This distance is"<<d<<endl;
}
谁能解释下这个错误么，看不懂啊改了几天改不过来