The **digit sum** of a given integer number is the **sum **of all its individual** digits**. **Java** Source code to **calculate** sum of digits of a number is given with example and detailed explanation. The sum of the digits of a number are calculated or used in many further programs.

**Digit Sum Example:-**

Iteration 1 :

- 1894%10 = 4
- 1894/10= 189
- value of S=0+ 4

Iteration 2 :

- 189%10=9
- 189/10= 18
- Value of S=4+9

Iteration 3 :

- 18%10=8
- 18/10=1
- Value of S=13+8

Iteration 4 :

- 1%10=1
- 1/10=0
- Value of S= 21+1

Iteration 5 :

- Terminates because of false Condition of loop.

import java.util.*; class DigitSum { public static void main(String args[]) { int n,i=0, sum=0; n=Integer.parseInt(args[0]); //taking integer from command line while(n!=0) //calculate digit sum { i=n%10; n=n/10; sum=sum+i; } System.out.println(sum); } }

**Output:-**import java.util.*; public class DigitSum{ public static void main(String args[]) { Scanner sy = new Scanner(System.in); System.out.println("Please enter a number to calculate digit sum:"); int number = sy.nextInt(); // Remember number/10 reduces one digit from number // and number%10 gives you last digit int s = 0; int i = n; while (i != 0) //calculate digit sum while input> 0 { int lastdigit = i % 10; s += lastdigit; i /= 10; } System.out.printf("Digit Sum of number %d is %d", n, s); // Scanner close to prevent resource leak sy.close(); } }

**Output****:**

Please enter a number to calculate digit sum:12321

Digit Sum of number 12321 is 9Please enter a number to calculate digit sum:123456789987654321

Digit Sum of number 123456789987654321 is 90import java.util.*; public class DigitSum { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int a; System.out.print("Enter a positive integer: "); a = in.nextInt(); if (a <= 0) System.out.println("Integer you've entered is non-positive."); else { int s = 0; while (a != 0) { s += a % 10; a /= 10; } System.out.println("Digit Sum of integer: " + s); } } }

**Output:-**Enter a positive integer: 12321

Digit Sum of integer: 9

Enter a positive integer: -342424

Integer you’ve entered is non-positive.

Enter a positive integer: 342424

Digit Sum of integer: 19

Just One line solution for Sum of the digits

int num = 12346; // any number int sum = 0; for (int n = num; n > 0; sum += n % 10, n /= 10) ;