# Java Program to Find Sum of Digits of a Number

• Java Program to find the sum of digits of a number using while loop and using a function.

Given a number N, we have to add all digits of a N and print the sum on screen.
For Example,
Sum of digits of 2534 = 2 + 5 + 3 + 4 = 14

To find sum of digits of a number, we will extract digits one by one from N using '/' and '%' operator and add it to a sum variable. N%10 will give the least significant digit of N. To remove least significant digit from N we will divide N by 10.

For Example,
Last digit of a number : 5342 % 10 = 2
Removing last digit from a number : 5342/10 = 534

## Java program to add digits of a number using while loop

package com.tcc.java.programs;

import java.util.Scanner;

/**
* Java Program to check a number is perfect number or not
*/
public class DigitSum {
public static void main(String[] args) {
int num, i, digSum = 0;
Scanner scanner;
scanner = new Scanner(System.in);

System.out.println("Enter an Integer");
num = scanner.nextInt();

while (num != 0) {
/*
* get the least significant digit(last digit) of num and add it to
* digSum
*/
digSum += num % 10;
/*
* remove least significant digit(last digit) form num
*/
num = num / 10;
}

System.out.format("Sum of Digits = %d", digSum);
}
}
Output
Enter an Integer
786
Sum of Digits = 21
Enter an Integer
1010
Sum of Digits = 2

## Java program to find sum of digits of a number using function

package com.tcc.java.programs;

import java.util.Scanner;

/**
* Java Program to check a number is perfect number or not using function
*/
public class DigitSumFunction {
public static void main(String[] args) {
int num;
Scanner scanner;
scanner = new Scanner(System.in);

System.out.println("Enter an Integer");
num = scanner.nextInt();

System.out.format("Sum of Digits = %d", getDigitSum(num));
}

/**
* This function returns the sum of digits of num
*/
public static int getDigitSum(int num) {
int digSum = 0;
while (num != 0) {
/*
* get the least significant digit(last digit) of num and add it to
* digSum
*/
digSum += num % 10;
/*
* remove least significant digit(last digit) form num
*/
num = num / 10;
}
return digSum;
}
}
Output
Enter an Integer
100
Sum of Digits = 1
Enter an Integer
1011
Sum of Digits = 3

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