operators and expressions - модификация задача 4

/*Write an expression that checks for given integer if its third
 * digit (left-to-right) is 7.
 */

using System;

class IsThirdDigit7FromLeft
{
    static void Main()
        {
            long numberInput;
            do
            {
                Console.Write("Please enter integer number: ");
            }
            while (!long.TryParse(Console.ReadLine(), out numberInput));

            int numDigits = 0;
            long x = 1L; // help to count the digits
            long numberDivided = numberInput;// a number is used to count the digits
            while (x != 0)
            {

                x = numberDivided / 10;
                numberDivided = x;
                numDigits++;

            }

            int a = (int)(numberInput / Math.Pow(10, (numDigits - 3)));
            int b = (int) (a % 10);
            Console.WriteLine(a);
            Console.WriteLine(b);
            bool thirdDigit = (numberInput / Math.Pow(10, (numDigits - 3))) % 10 == 7; //(numDigits - 3) cos we need the third digit
            int value3rd = (int)(numberInput / Math.Pow(10, (numDigits - 3))) % 10; // finding what number is the third digit.

            Console.WriteLine("Is SEVEN (7) the third digit of the entered number {0}? {1}", numberInput, thirdDigit);
            if (!thirdDigit)
            {
                Console.WriteLine("The third digit (left-to-right) in the entered number {0} is {1}.", numberInput, value3rd);
            }
            else
            {
                // nothing happens
            }
        }
}