杭电oj 2001 计算两点间的距离

#include 
#include 
int main()
{
     float x1,y1,x2,y2;
     double d;
     while (scanf("%f%f%f%f",&x1,&y1,&x2,&y2)!=EOF)
     {
     d=sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
     printf("%.2lf\n",d);
     }
}