0-to-100-to-Text

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

namespace Number_0_100_to_Text
{
    class Program
    {
        static void Main(string[] args)
        {
            int number = int.Parse(Console.ReadLine());

            if (number >= 0 && number <= 100)
            {

                switch (number)
                {
                    case 0: Console.WriteLine("zero"); break;

                    case 10: Console.WriteLine("ten"); break;
                    case 11: Console.WriteLine("eleven"); break;
                    case 12: Console.WriteLine("twelve"); break;
                    case 13: Console.WriteLine("thirteen"); break;
                    case 14: Console.WriteLine("fourteen"); break;
                    case 15: Console.WriteLine("fifteen"); break;
                    case 16: Console.WriteLine("sixteen"); break;
                    case 17: Console.WriteLine("seventeen"); break;
                    case 18: Console.WriteLine("eighteen"); break;
                    case 19: Console.WriteLine("nineteen"); break;
                    case 100: Console.WriteLine("one hundred"); break;
                    default:

                        int tens = number / 10;
                        int ones = number % 10;

                        switch (tens)
                        {
                            case 2: Console.Write("twenty"); break;
                            case 3: Console.Write("thirty"); break;
                            case 4: Console.Write("fourty"); break;
                            case 5: Console.Write("fifty"); break;
                            case 6: Console.Write("sixty"); break;
                            case 7: Console.Write("seventy"); break;
                            case 8: Console.Write("eighty"); break;
                            case 9: Console.Write("ninety"); break;

                        }

                        if (tens > 0 && ones > 0)
                        {
                            Console.Write(" ");
                        }
                        switch (ones)
                        {
                            case 1: Console.WriteLine("one"); break;
                            case 2: Console.WriteLine("two"); break;
                            case 3: Console.WriteLine("three"); break;
                            case 4: Console.WriteLine("four"); break;
                            case 5: Console.WriteLine("five"); break;
                            case 6: Console.WriteLine("six"); break;
                            case 7: Console.WriteLine("seven"); break;
                            case 8: Console.WriteLine("eight"); break;
                            case 9: Console.WriteLine("nine"); break;
                            default: Console.WriteLine(); break;
                        }
                        break;
                }
            }
            else
            {
                Console.WriteLine("invalid number");
            }
        }
    }
}