using System;

public class Program

{

    public static void Main()

    {

            int checkDigitB = 0;

            int checkDigitC = 0;

            int checkDigitD = 0;

            int remainder = 0;

​

            //Console.WriteLine("Please enter your transfer number:");

            String transferNumber = "9924086824";

            transferNumber = "0" + transferNumber;        

​

            for (int i = 0; i < (transferNumber.Length); i++)

            {

                checkDigitB = Convert.ToInt16(transferNumber.Substring((i), 1));

                if (checkDigitB > 4)

                    checkDigitC = ((checkDigitB * 2) - 9);

                else

                    checkDigitC = (checkDigitB * 2);

                remainder = ((i - 1) % 2);

                if (remainder == 0)

                    checkDigitD += checkDigitC;

                else

                    checkDigitD += checkDigitB;

            }

​

            if(checkDigitD % 10 == 0){

                Console.WriteLine("Check Digit: 0" );

            } else {

                int result = (10 - (checkDigitD % 10));

                Console.WriteLine("Check Digit: " + result);

            }

            Console.ReadLine();

    }

}