Finding the sum of the digits of a number is a common problem in programming and mathematics. This task involves breaking down a given number into its individual digits and then adding them together. This concept is often used in various programming scenarios, including data validation, cryptography, and number manipulation.

## Problem Statement

Write a C# program that takes an integer as input and calculates the sum of its digits.

## C# Program to Find Sum of Digits of a Number

using System; class Program { static void Main() { Console.Write("Enter a number: "); int number = int.Parse(Console.ReadLine()); int sumOfDigits = CalculateSumOfDigits(number); Console.WriteLine($"The sum of the digits of {number} is {sumOfDigits}"); } static int CalculateSumOfDigits(int number) { int sum = 0; while (number > 0) { int digit = number % 10; // Get the last digit sum += digit; // Add the digit to the sum number /= 10; // Remove the last digit } return sum; } }

## How it Works

**Input**: We start with the number 12345.**Iteration**:- In the first iteration, we use the modulo operator (%) to get the last digit: 12345 % 10 = 5. This digit is added to our running total (initialized to 0):
`sum = 0 + 5 = 5`

. - We then perform integer division by 10 to remove the last digit: 12345 / 10 = 1234. The number becomes 1234.
- In the second iteration, we again use modulo to get the last digit: 1234 % 10 = 4. We add this digit to the sum:
`sum = 5 + 4 = 9`

. - We once more perform integer division by 10: 1234 / 10 = 123. The number becomes 123.
- This process continues until there are no more digits left to process.

- In the first iteration, we use the modulo operator (%) to get the last digit: 12345 % 10 = 5. This digit is added to our running total (initialized to 0):
**Termination Condition**: We keep iterating and updating the sum until the number becomes zero (in integer division, or until we reach the end of the number in string form).**Output**: When the number becomes zero, we have extracted and summed all the digits. The final value of`sum`

is the sum of digits of the original number.