Question

用java语言写一个程序，程序的内容，是输入一个0～1000的整数，求各位数的和。

Answer 1

 int num;
 Scanner in=new Scanner(System.in);
 num=in.nextInt();
 bai=num/100;
 shi=(num-bai*100)/10;
 ge=num-bai*100-shi*10;
 int sum=bai+shi+ge;//sum就是你要求的和了 自己输出吧

Answer 2

import java.util.*;
public class Number2 {
public void run(int number){
if(number > 1000){
System.out.println("输入数字大于1000！");
System.exit(0);
}
int [] a= new int[3];

a[2] = number /100;
a[1] = (number - a[2]*100)/10;
a[0] = (number - a[2]*100 - a[1]*10)/1;

int total = 0;
total = a[0] + a[1] + a[2];

System.out.println("你输入的数字是：" + number + " 它的各位数之和是：" + total);
}

public static void main(String args[])
{
Number2 num = new Number2();
System.out.println("请输入一个1000以内的数");
Scanner reader=new Scanner(System.in);
int number = reader.nextInt();

num.run(number);

}
}

Answer 3

public static void main(String[] args) {
int sum = 0;
for (int j = 0; j <=1000; j++) {
sum+=j;
}
System.out.println(sum);
}