java 小數取尾

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Scanner;


public class Main {


public static void main(String[] args) {
Scanner sc = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
Double r;
final Double PI=3.1415927;
while(sc.hasNextLine()){
r=sc.nextDouble();
//double b=(4/3)*PI*Math.pow(r, 3);如果寫成這樣，會先計算4/3,並自動四捨五入爲1
double b=4*PI*Math.pow(r, 3)/3;
System.out.printf("%.3f%n",b);
sc.nextLine();
}
}




}