C++计算两点距离（定义两个类）

汗，改了好久才发现distance不能用，distance是个库函数，该成distan就可以了。
附代码：

#include "iostream"
using namespace std;
class point
{
float x;
float y;
friend class distan;
public:
point(float a,float b)
{
x=a;
y=b;
}
};
class distan
{
float result;
public:
distan(const point &A,const point &B)
{
float x1=A.x,x2=B.x,y1=A.y,y2=B.y;
result=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);

}
float getresult()
{
return result;
}
};
int main()
{

float x1,x2,y1,y2;
cout<<"AdeX:"< cin>>x1;
cout<<"AdeY:"< cin>>y1;
cout<<"BdeX:"< cin>>x2;
cout<<"BdeY:"< cin>>y2;
point A(x1,x2);
point B(x2,y2);
distan C(A,B);

return 0;
}