package demo; import java.util.Scanner; public class Tex { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("请输入一个0-1000之间的整数"); int a =(int)input.nextDouble(); if(a>999||a<0) { System.out.println("输入有误"); } else if(a>0 && a<10){ System.out.println("The sum of the digits is "+ a); } else if(a>9 && a<100) { int b=(a/10) + (a%10); System.out.println("The sum of the digits is "+ b); } else if(a>99 && a<1000) { int c=(a/100)+(a%100)+(a%10%10); System.out.println("The sum of the digits is "+ c); } } }