HDU2001java

import java.util.*;

import java.text.DecimalFormat;

class Main{

public static void main(String args[])

{Scanner cin=new Scanner(System.in);

while(cin.hasNext())

{ double x1=cin.nextDouble();

double y1=cin.nextDouble();

double x2=cin.nextDouble();

double y2=cin.nextDouble();

double c=Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));

DecimalFormat df=new DecimalFormat("#0.00");

System.out.println(df.format(c));

}

}

}

此處注意要用到DecimalFormat來确定浮點後面的想要保留的小數；

import java.util.*;

class Main{

public static void main(String args[])

{Scanner cin=new Scanner(System.in);

while(cin.hasNext())

{double x1=cin.nextDouble();

double y1=cin.nextDouble();

double x2=cin.nextDouble();

double y2=cin.nextDouble();

aa(x2-x1,y2-y1);

}}

public static void aa(double a,double b)

{ double c=Math.sqrt(a*a+b*b);

System.out.printf("%.2f",c);

System.out.println();

}

}

也可以直接用printf直接保留兩位小數；