How to Calculate the Sum of Digits of Given Number

package com.swain.cell;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

public class SumOFNumber {

       public static void main(String[] args) {

              try {

                     BufferedReader din = new BufferedReader(new InputStreamReader(

                                  System.in));

                     int n, r, s;

                     System.out

                                  .println("Please enter the number to find the sum of a digit: ");

                     n = Integer.parseInt(din.readLine());

                     r = 0;

                     s = 0;

                     while (n > 0) {

                           r = n % 10;

                           s = s + r;

                           n = n / 10;

                     }

                     System.out.println("The sum of the digit is : " + s);

              } catch (IOException e) {

                     System.out.println("Wrong Input");

              }

       }

}