Question

Write the sumDigits method. This method takes an int and returns the sum of its digits. For example, 124 will return 7.

Method calls to sumDigits will result in the following:

a. sumDigits(124) returns 7
b. sumDigits(10) returns 1
c. sumDigits(135) returns 8

Answer 1

The sumDigits method calculates the sum of the digits in an integer by continually adding the last digit to the sum and removing it from the number.

Step-by-step explanation:

Writing the sumDigits Method

To write a method that sums the digits of an integer in Java, we will iterate through each digit of the number, add it to a sum, and then update the number by removing the last digit. A loop can be used to perform this action until the number is reduced to zero. Here is a step-by-step example:

1. Initialize a variable to store the sum of digits, say sum, to 0.
2. Use a loop to continuously perform the following steps until the number becomes 0:
3. Find the last digit of the number by using the modulus operator (number % 10) and add it to sum.
4. Remove the last digit from the number by dividing it by 10 (number / 10).

This process will be repeated for all digits in the number, and the final sum is the answer.

For example:

• sumDigits(124) will process the digits 4, 2, and 1 to return 7.
• sumDigits(10) will process the digits 0 and 1 to return 1.
• sumDigits(135) will process the digits 5, 3, and 1 to return 9 (Please note there is a correction to be made here as the correct sum is 9, not 8 as stated in the problem).