HDU2001
#include <stdio.h>
#include <math.h>
int main(){
//freopen("in.txt","r",stdin);
double x1 = 0,x2 = 0,y1 = 0,y2 = 0;
while(scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2)!=EOF){
printf("%.2lf\n",sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)));
}
return 0;
}
如发现问题,敬请指出,互相提高。