Welcome! In today's lesson, we'll delve into a unique coding challenge that centers around traversing the digits of a number using a while loop under a specific condition. You'll have the opportunity to practice and enhance your skills in working with C#'s loops and conditional statements — fundamental concepts in programming. Are you as excited as I am? Let's dive in!

Today, our objective is to create a method that operates on an integer input. The task might seem simple, but it requires some ingenuity. Here's the mission: given an integer, n, we need to calculate and return the sum of its even digits — and here's the clincher — without converting n into a string. For instance, if n equals 4625, the output should be 12 because the sum of the even digits 4, 6, and 2 equals 12.

Keep in mind that n will always be a positive integer between 1 and 100,000,000. Ready to give it a shot? Great! Let's get started!

To start, we need the basic structure of our method, where we begin by defining a variable digitSum to keep track of the sum of even digits.

Below is the initial platform for our method:

The tool we've chosen to traverse through the digits of the input integer n is the while loop, which is set to run as long as n is greater than zero. Let's incorporate this into our method:

Inside our loop, we'll first extract the last digit of n using the modulo operation (n % 10). If the digit is even, we'll increase our digitSum by this digit.

After processing a digit, we'll then chop off the last digit of n using integer division (n / 10), which allows the while loop to proceed to the next digit. Here's how this appears in the code:

After summing up all the even digits, the final step is to return our digitSum.

Our complete method now looks like this:

To run our code and see it in action, we need to include a Main method. This method will create an instance of the Solution class, call SumEvenDigits with a test value, and print the result.

Here is the complete code with the Main method:

Well done on completing this lesson! You've successfully navigated the foundational concepts of using a while loop to traverse the digits of a number and have gained an understanding of how to apply conditions within it. Now it's your turn to apply what you've learned. I invite you to explore additional challenges to solidify and build upon your new skill set. Remember, the only limit to your growth is the boundary of your dedication. Keep practicing; your C# prowess is growing with each challenge you conquer!