C# задача от SoftUni Number 0...100 to Text

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _16.Number_0_to_100_to_Text
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Въведи число от 0 до 100: ");
            int number = int.Parse(Console.ReadLine());

            if (number < 0 || number > 100)
            {
                Console.WriteLine("Invalid number");
            }
            else
            {
                string numberAsText = String.Empty; //Еднакво с = "";

                if (number == 0)
                {
                    numberAsText = "zero";
                }
                if (number >= 10 && number < 20)
                {
                    switch (number)
                    {
                        case 10: numberAsText = "ten"; break;
                        case 11: numberAsText = "eleven"; break;
                        case 12: numberAsText = "twelve"; break;
                        case 13: numberAsText = "thirteen"; break;
                        case 14: numberAsText = "forteen"; break;
                        case 15: numberAsText = "fifteen"; break;
                        case 16: numberAsText = "sixteen"; break;
                        case 17: numberAsText = "seventeen"; break;
                        case 18: numberAsText = "eighteen"; break;
                        case 19: numberAsText = "nineteen"; break;

                    }
                }
                else if ((number > 0 && number < 10) || (number >= 20 && number < 100))
                {
                    int firstDigit = number / 10;

                    switch (firstDigit)
                    {
                        case 0: numberAsText = String.Empty; break; //може да се изпиши = ""; break;
                        case 2: numberAsText = "twenty"; break;
                        case 3: numberAsText = "thirty"; break;
                        case 4: numberAsText = "forty"; break;
                        case 5: numberAsText = "fifty"; break;
                        case 6: numberAsText = "sixty"; break;
                        case 7: numberAsText = "seventy"; break;
                        case 8: numberAsText = "eighty"; break;
                        case 9: numberAsText = "ninety"; break;
                    }

                    int secondDigit = number % 10;

                    switch (secondDigit)
                    {
                        case 1: numberAsText += " one"; break;
                        case 2: numberAsText += " two"; break;
                        case 3: numberAsText += " three"; break;
                        case 4: numberAsText += " four"; break;
                        case 5: numberAsText += " five"; break;
                        case 6: numberAsText += " six"; break;
                        case 7: numberAsText += " seven"; break;
                        case 8: numberAsText += " eight"; break;
                        case 9: numberAsText += " nine"; break;
                    }


                }
                else if (number == 100)
                {
                    numberAsText = "one hundred";
                }

                Console.WriteLine(numberAsText.Trim()); // Trim - е метод и премахва празни интервали пред и след стринга (текста)

            }

        }
    }
}


    Втори вариант на решение на задачата:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _16._1.Number_0_to_100_to_Text
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Решение с използване на масиви.");
            Console.Write("Въведи цяло число от 0 до 100: ");
            int number = int.Parse(Console.ReadLine());

            if (number < 0 || number > 100)
            {
                Console.WriteLine("Invalid number");
            }
            else
            {
                string nameNumber = "";

                var zeroToNineteen = new[] { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };

                var twentyToNinety = new[] { "zero", "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety" };

                if (number >= 0 && number < 20)
                {
                    nameNumber = zeroToNineteen[number];
                }
                else if (number >= 20 && number < 100)
                {
                    int firstDigit = (number / 10);
                    nameNumber = twentyToNinety[firstDigit];

                    int secondDigit = (number % 10);
                    if (secondDigit != 0)
                    {
                        nameNumber = nameNumber + " " + zeroToNineteen[secondDigit];
                    }

                }
                else if (number == 100)
                {
                    nameNumber = "one hundred";
                }

                Console.WriteLine(nameNumber);
            }
        }
    }
}