Digit as Number

using System;

class DigitAsWord
{
    static void Main()
    {
        // intro
        string intro = @"This program asks for a number (0-9),
including 2.8 (rounded to one digit after the decimal point)
and depending on the input, shows the digits as a words.";
        Console.WriteLine(intro);

    // declarations
        string input;
        double number;

    // input
        do // validating input for a type double number, between 0 and 9
        {
            Console.Write("\nPlease, enter a number (0-9): ");
            input = Console.ReadLine();

        } while (!double.TryParse(input, out number) || number < 0 || number > 9);

    // logic
        // rounding number to 1 digit after the decimal point
        // so that we can work with digits only on both sides of the decimal point
        number = Math.Round(number, 1, MidpointRounding.AwayFromZero);

        // now we are positive that we have exactly 3 symbols:
        // one digit before the decimal point, one decimal point, one digit after the decimal point
        string temp = input.ToString(); // converting back to string, so that we can name the decimal point as well

        Console.WriteLine();

        // applying the DigitName() method to the first digit (index 0 in the string)
        DigitName(temp[0] - '0'); // char - '0' converts the respective char to int (digit)
        Console.Write("point "); // naming the decimal point
        DigitName(temp[2] - '0'); // naming the digit after the decimal point

        Console.WriteLine("\n");
    }

    private static void DigitName(int digit)
    {

        switch (digit)
        {
            case 0:
                {
                    Console.Write("zero ");
                    break;
                }

            case 1:
                {
                    Console.Write("one ");
                    break;
                }

            case 2:
                {
                    Console.Write("two ");
                    break;
                }

            case 3:
                {
                    Console.Write("three ");
                    break;
                }

            case 4:
                {
                    Console.Write("four ");
                    break;
                }

            case 5:
                {
                    Console.Write("five ");
                    break;
                }

            case 6:
                {
                    Console.Write("six ");
                    break;
                }

            case 7:
                {
                    Console.WriteLine("seven ");
                    break;
                }

            case 8:
                {
                    Console.Write("eight ");
                    break;
                }

            case 9:
                {
                    Console.Write("nine ");
                    break;
                }

            default:
                {
                    Console.WriteLine("not a digit ");
                    break;
                }
        }
    }
}