有大佬看看哪有问题吗#include<iostream>#include<cmath>using namespace std;class Point{double X,Y;public: Point(double a = 0,double b = 0); double GetX(); double GetY(); friend double GetLength( Point &A,Point &B); };double GetLength( Point &A,Point &B){double a = A.X - B.X;double b = A.Y - B.Y;return static_cast<double>(sqrt(a*a+b*b)) ;}int main(){Point P1(4,5),P2(1,1);cout<<"两点之间的距离为："<<GetLength(P1,P2)<<endl; return 0;}