Chapter 2 Exercise 6, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

(Sum the digits in an integer) Write a program that reads an integer between 0 and 1000 and adds all the digits in the integer. For example, if an integer is 932, the sum of all its digits is 14.
Hint: Use the % operator to extract digits, and use the / operator to remove the extracted digit. For instance, 932 % 10 = 2 and 932 / 10 = 93.

import java.util.Scanner;
public class Exersice_06 {

    public static void main(String[] Strings) {

        Scanner input = new Scanner(System.in);

        System.out.print("Enter an integer between 0 and 1000: ");
        int number = input.nextInt();

        int firstDigit = number % 10;
        int remainingNumber = number / 10;
        int SecondDigit = remainingNumber % 10;
        remainingNumber = remainingNumber / 10;
        int thirdDigit = remainingNumber % 10;

        int sum = thirdDigit + SecondDigit + firstDigit;

        System.out.println("The sum of all digits in " + number + " is " + sum);

    }
}