求指导菜鸟的C++题目

供参考：

#include<iostream>
#include<cmath>

using namespace std;

class Point{
      private:
              double x,y;
       public:
               Point(double a=0,double b=0):x(a),y(b){};
               double GetX()const;
               double GetY()const;
               void   print()const;
               friend double GetLength(const Point&,Point&);
};

double Point::GetX()const
{
     return x;
}

double Point::GetY()const
{
     return y;
}

void Point::print()const
{
     cout<<"("<<x<<","<<y<<")"<<endl;
}
double GetLength(const Point &A,Point &B)
{
     double Length;
     Length = sqrt((A.x-B.x)*(A.x-B.x)+(A.y-B.y)*(A.y-B.y));
     return Length;
}
int main()
{
     const Point p1;
     cout<<"p1:("<<p1.GetX()<<","<<p1.GetY()<<")"<<endl;

     Point p2(4,3);
     cout<<"p2:("<<p2.GetX()<<","<<p2.GetY()<<")"<<endl;
     
     cout<<"p1<==>p2 Length="<<GetLength(p1,p2)<<endl;
     
     return 0;
}

//p1:(0,0)
//p2:(4,3)
//p1<==>p2 Length=5
//请按任意键继续. . .