Java Program For Performing Sum Of Last Four Digits Of A Number

import java.util.Scanner;

public class sumOfLastFourDigitsOfRollNumber {

    public static void main(String [] args){

        Scanner scan = new Scanner(System.in);
        System.out.println("ENTER YOUR ROLL NUMBER:"):
        int n = scan.nextInt();

//   now we will assign our value to any other number, so that the value of that number can be change
        int temp =n;
        int sum =0;
// we can chnage any number to string to calculate it's length
        for (int  i = String.valueOf(n).length() ; i>4 ; i--){

            int lastDigit = temp %10;
            temp =temp /10;
            sum +=lastDigit;

        }
        System.out.println(sum);
    }
}

OR,

import java.util.Scanner;

public class sumOfLastFourDigitsOfRollNumber {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        System.out.println("ENTER YOUR ROLL NUMBER:");
        int n = scan.nextInt();
        int count =  String.valueOf(n).length();
//        now we will assign our value to any other number, so that the value of that number can be change

        int temp = n;
        int sum = 0;
        if(count <8){
            System.out.println("ENTER YOUR ROLL NUMBER ATLEAST OF 8 DIGITS.");}

//
        else {

// we can chnage any number to string to calculate it's length
            for (int i = count; i > 4; i--) {

                int lastDigit = temp % 10;
                temp = temp / 10;
                sum += lastDigit;

            }

            System.out.println(sum);
        }
        }
    }