把随机得到的数，个十百位分别相加

import java.util.Random;

import javax.swing.JOptionPane;
public class Numbers {
    public static void main(String[] args){
        double digit;
        digit = (int)(Math.random() * 1000);
        JOptionPane.showMessageDialog(null,"得到的随机数是：" + digit);
        System.out.println("The sum of the digits is " + ((int)(digit % 10) + (int)((digit % 100) / 10) + (int)(digit / 100)));
    }

}