HDOJ2001

water~~~

#include <stdio.h>#include <math.h>#include <iostream>double abs(double x);int main(int argc, char *argv[]) {double x1,y1,x2,y2;while(std::cin>>x1>>y1>>x2>>y2){double x = abs(x1-x2);double y = abs(y1-y2);printf("%.2lf\n",sqrt(x*x+y*y));}return 0;}double abs(double x){return x > 0.0 ? x:-x;}