Write a method that computes the sum of the digits in an integer. Use the following method header: public static int sumDigits(long n) For example, sumDigits(234) returns 9 the result of 2 3 4. (Hint: Use the % operator to extract digits, and the / operator to remove the extracted digit. For instance, to extract 4 from 234, use 234 % 10, which is 4. To remove 4 from 234, use 234 / 10, which is 23. Use a loop to repeatedly extract and remove the digit until all the digits are extracted.

The java program for the given scenario is shown below.

import java.util.*;

import java.lang.*;

public class Test

{

   //variables to hold the number, digits and sum of the digits

   //variable to hold number is assigned any random value

   static long num=123;

   static int sum=0;

   static int digit;

   static int s;

   //method to add digits of a number

   public static int sumDigits(long n)

   { do

       {

           digit=(int) (n%10);

           sum=sum+digit;

           n=n/10;

       }while(n>0);

       return sum;

   }

public static void main(String[] args) {

    s = sumDigits(num);

 System.out.println("The sum of the digits of "+num+ " is "+s);  }

}

OUTPUT

The sum of the digits of 123 is 6

Explanation:

1. The variables to hold the number is declared as long and initialized.

2. The variables to store the digits of the number and the sum of the digits are declared as integer. The variable, sum, is initialized to 0.

3. The method, sumDigits(), is defined which takes a long parameter and returns an integer value. The method takes the number as a parameter and returns the sum of its digits.

4. Inside method, sumDigits(), inside the do-while loop, the sum of the digits of the parameter is computed.

5. Inside main(), the method, sumDigits(), is called. The integer value returned by this method is stored in another integer variable, s.

6. The sum of the digits is then displayed to the console.

7. All the variables are declared outside main() and at the class level and hence declared static. The method, sumDigits(), is also declared static since it is to be called inside main().

8. In java, the whole code is written inside a class since java is a purely object-oriented language.

9. In this program, object of the class is not created since only a single class is involved having main() method.

10. The program can be tested for any value of the variable, num.

11. The file is saved as Test.java, where Test is the name of the class having main() method.