HDU 2001（Java）

package GUI;import java.io.*;import java.util.*;import org.omg.CORBA.PUBLIC_MEMBER;public class Main {    public static void main(String[] args) {        Scanner inScanner=new Scanner(System.in);        double x1,x2,y1,y2;        while(inScanner.hasNextDouble())        {        x1=inScanner.nextDouble();        y1=inScanner.nextDouble();        x2=inScanner.nextDouble();        y2=inScanner.nextDouble();        double sum;        sum=Math.sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));        System.out.printf("%.2f",sum);        System.out.println();        }    }}