**Objectives :**

- Write a program to compute sum of digits of a given number.
- Write a program to find sum of digits of a given number.
- Write a program to calculate sum of digits of a given number.
- Write a program to compute sum of digits of a given integer number.
- Write a program to compute sum of digits of a number entered via Command Line.
- Write a program to compute sum of digits of a given number. Take input from Command Line.
- Write a program to compute sum of digits of a given number. Take input using Scanner class.

Following is the Java Program to compute Sum of Digits of a given integer number;

**Method 1 : Java Program to find Sum of Digits when number is entered from command line**

[sourcecode lang=”java”]

class SumOfDigits

{

public static void main(String args[])

{

int n;

int a=0;

int sum=0;

//taking integer number from command line and parsing the same

n=Integer.parseInt(args[0]);

while(n!=0)

{

a=n%10;

n=n/10;

sum=sum+a;

}

System.out.println("Sum of digits: " + sum);

}

}

[/sourcecode]

Steps to run above program via command line :

- Compilation : C:\JavaPrograms>javac SumOfDigits.java
- Interpretation : C:\JavaPrograms>java SumOfDigits 12345

Output : Sum of digits: 15

**Method 2 : Java Program to find Sum of Digits if input is taken using Scanner class**

[sourcecode lang=”java”]

import java.util.Scanner;

public class SumOfDigits {

public static void main(String args[]) {

Scanner in = new Scanner(System.in);

int n;

int a=0;

System.out.print("Enter a positive number: ");

n = in.nextInt();

if (n <= 0)

System.out.println("You have entered a negative number.");

else {

int sum = 0;

while (n != 0) {

a=n%10;

n=n/10;

sum=sum+a;

}

System.out.println("Sum of digits: " + sum);

}

}

}

[/sourcecode]

Steps to run above program via command line :

- Compilation : C:\JavaPrograms>javac SumOfDigits.java
- Interpretation : C:\JavaPrograms>java SumOfDigits 12345

Output :

Trial 1 : With positive number

Enter a positive number: 12345

Sum of digits: 15

Trial 2 : With negative number

Enter a positive number: -12345

You have entered a negative number.