using System;
using System.Reflection;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Threading;
using System.Text;
using System.Data;
namespace ConsoleApplication1
{
    class NumbersPositionsInWords
    {
        public string zeroPosition;//One, Two, Three
        public string tenthPosition;// Holds Twenty, Thirty, etc.
        public string elevenSeries;//Special words like 11 = Eleven, 12 = Tweleve, etc.
    }

    class Program
    {
        static Dictionary<int, NumbersPositionsInWords> numbersToWordsDictionary = new Dictionary<int, NumbersPositionsInWords>();
        static string hundredString = "Hundred";
        static StringBuilder numberToWordText = new StringBuilder();

        static Program()
        {
            numbersToWordsDictionary.Add(1,
                new NumbersPositionsInWords() { zeroPosition = "One", tenthPosition = "Ten", elevenSeries = "Eleven" });

            numbersToWordsDictionary.Add(0,
                new NumbersPositionsInWords() { zeroPosition = "Zero", tenthPosition = null, elevenSeries = "Ten" });

            numbersToWordsDictionary.Add(2,
                new NumbersPositionsInWords() { zeroPosition = "Two", tenthPosition = "Twenty", elevenSeries = "Tweleve" });

            numbersToWordsDictionary.Add(3,
                new NumbersPositionsInWords() { zeroPosition = "Three", tenthPosition = "Thirty", elevenSeries = "Thirteen" });

            numbersToWordsDictionary.Add(4,
                new NumbersPositionsInWords() { zeroPosition = "Four", tenthPosition = "Fourty", elevenSeries = "Fourteen" });

            numbersToWordsDictionary.Add(5,
                new NumbersPositionsInWords() { zeroPosition = "Five", tenthPosition = "Fifty", elevenSeries = "Fifteen" });

            numbersToWordsDictionary.Add(6,
                new NumbersPositionsInWords() { zeroPosition = "Six", tenthPosition = "Sixty", elevenSeries = "Sixteen" });

            numbersToWordsDictionary.Add(7,
                new NumbersPositionsInWords() { zeroPosition = "Seven", tenthPosition = "Seventy", elevenSeries = "Seventeen" });

            numbersToWordsDictionary.Add(8,
                new NumbersPositionsInWords() { zeroPosition = "Eight", tenthPosition = "Eighty", elevenSeries = "Eighteen" });

            numbersToWordsDictionary.Add(9,
                new NumbersPositionsInWords() { zeroPosition = "Nine", tenthPosition = "Ninty", elevenSeries = "Ninteen" });

        }

        public static void Main(string[] args)
        {
            Console.WriteLine("Enter a 3digit number");
            string inputString = Console.ReadLine();
            ValidateInput(inputString);

            int hundredthPostionDigit = GetDigitFromPosition(inputString, 0);
            StringBuilder resultString = new StringBuilder();

            if (hundredthPostionDigit > 0)
                resultString.AppendFormat("{0}{1} {2}", numbersToWordsDictionary[hundredthPostionDigit].zeroPosition,
                    string.Empty, hundredString);

            int tenthPositionDigit = GetDigitFromPosition(inputString, 1);
            int unitsPositionDigit = GetDigitFromPosition(inputString, 2);

            ParseTenthUnitPositionDigit(tenthPositionDigit, unitsPositionDigit);

            if (resultString.Length > 0 && numberToWordText.Length > 0)
                resultString.AppendFormat(" {0} {1}", "And", numberToWordText);
            else resultString.Append(numberToWordText);

            Console.WriteLine(resultString);
            Console.ReadLine();
        }

        private static void ValidateInput(string str)
        {
            int dummy;
            if (str.Length > 3 || str.Length < 3 || !Int32.TryParse(str, out dummy))
            {
                Console.WriteLine("Enter numbers with only 3 digits. Press Enter key to close application.");
                Console.ReadLine();
                Environment.Exit(0);
            }
        }

        private static void ParseTenthUnitPositionDigit(int tenthPositionDigit, int unitsPositionDigit)
        {
            if (tenthPositionDigit > 1)
                numberToWordText.AppendFormat("{0} {1}", numbersToWordsDictionary[tenthPositionDigit].tenthPosition,
                    unitsPositionDigit != 0 ? numbersToWordsDictionary[unitsPositionDigit].zeroPosition : string.Empty);

            if (tenthPositionDigit < 1)
                numberToWordText.AppendFormat("{0}", unitsPositionDigit > 0 ? numbersToWordsDictionary[unitsPositionDigit].zeroPosition : string.Empty);

            if (tenthPositionDigit == 1)
                numberToWordText.AppendFormat("{0}", unitsPositionDigit == tenthPositionDigit ?
                    numbersToWordsDictionary[tenthPositionDigit].elevenSeries : numbersToWordsDictionary[unitsPositionDigit].elevenSeries);
        }

        private static int GetDigitFromPosition(string str, int position)
        {
            return Int32.Parse(str[position].ToString());
        }
    }
}