how to convert number into words in C#

static int input;
static int temp;
static int index = 0;
static int[] buffer = new int[10];

static void ones(int value)//to print numbers in ones
{
      switch (value)
        {
            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.Write(" Seven"); break;
            case 8: Console.Write(" Eight"); break;
            case 9: Console.Write(" Nine"); break;
            default: break;
        }
           }

static void teens(int value)//to print numbers which are in teens
{
                  switch (value)
        {
            case 0: Console.Write("ten"); break;
            case 1: Console.Write(" eleven"); break;
            case 2: Console.Write(" Twelve"); break;
            case 3: Console.Write(" thirteen"); break;
            case 4: Console.Write(" Fourteen"); break;
            case 5: Console.Write(" Fifteen"); break;
            case 6: Console.Write(" Sixteen"); break;
            case 7: Console.Write(" Seventeen"); break;
            case 8: Console.Write(" Eighteen"); break;
            case 9: Console.Write(" Nineteen"); break;
        }
    }


static void tens(int value)//to print tens values
{
        switch (value)
        {
            case 2: Console.Write(" Twenty"); break;
            case 3: Console.Write(" thirty"); break;
            case 4: Console.Write(" Forty"); 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(" Ninty"); break;
            default: break;
        }
    }


static void Main(string[] args)
{
        Console.WriteLine("Enter a number to convert it into words");
        input = Convert.ToInt32(Console.ReadLine());//input from the user
        do
        {
            buffer[index] = input % 10;
            input /= 10;
            index++;
        } while (input != 0);
        wordgeneration();
        Console.ReadLine();
}

private static void wordgeneration()
{
                   for (temp = index - 1; temp >= 0; temp--)
        {
            if (temp == 5)//check for the values in lakhs
            {
                ones(buffer[temp]);
                Console.Write("Lakhs");
            }
            else if (temp == 3)//check for the numbers in thousands
            {
                if (buffer[temp + 1] == 1)
                {
                    teens(buffer[temp]);
                    Console.Write("Thousand");
                }
                else
                {
                    tens(buffer[temp + 1]);
                    ones(buffer[temp]);
                    if (!((buffer[temp + 1] == 0) && (buffer[temp] == 0)))
                    {
                        Console.Write("Thousand");
                    }
                }
            }
            else if (temp == 2)//check for the numbers in hundreds
            {
                if (buffer[temp] != 0)
                {
                    ones(buffer[temp]);
                    Console.Write("Hundred");
                }
            }
            else if (temp == 0)//chcek for the numbers in tens and ones
            {
                if (buffer[temp + 1] == 1)
                    teens(buffer[temp]);
                else
                {
                    tens(buffer[temp + 1]);
                    ones(buffer[temp]);

                }
            }

        }
    }

using System;
using System.Linq;

namespace CSN2W
{
    class Program
    {
        static void Main(string[] args)
        {
            string result;
            int i, num;
            int[] arrNum =
              {
                -1, 0, 5, 10, 15, 19, 20, 21, 25, 33, 49, 50, 72,
                99, 100, 101, 117, 199, 200, 214, 517, 589, 999,5700,
                1000, 1010, 1018, 1200, 9890, 10119, 13535, 57019,
                99999, 100000, 100001,1900001,19000010,1111111111,59899999
              };

            for (i = 0; i < arrNum.Count(); i++)
            {
                num = arrNum[i];
                result = NumberToWord(num);
                Console.WriteLine(num + "\t" + result);
            }
            Console.ReadKey();
        }


        static string NumberToWord(int num)
        {
            if (num == 0)
                return "Zero";

            if (num < 0)
                return "Not supported";

            var words = "";
            string[] strones = { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen" };
            string[] strtens = { "Twenty", "Thirty", "Fourty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety" };


            int crore = 0, lakhs = 0, thousands = 0, hundreds = 0, tens = 0, single = 0;


            crore = num / 10000000; num = num - crore * 10000000;
            lakhs = num / 100000;   num = num - lakhs * 100000;
            thousands = num / 1000; num = num - thousands * 1000;
            hundreds = num / 100;   num = num - hundreds * 100;
            if (num > 19)
            {
                tens = num / 10;    num = num - tens * 10;
            }
            single = num;


            if (crore > 0)
            {
                if (crore > 19)
                    words += NumberToWord(crore) + "Crore ";
                else
                    words += strones[crore - 1] + " Crore ";
            }

            if (lakhs > 0)
            {
                if (lakhs > 19)
                    words += NumberToWord(lakhs) + "Lakh ";
                else
                    words += strones[lakhs - 1] + " Lakh ";
            }

            if (thousands > 0)
            {
                if (thousands > 19)
                    words += NumberToWord(thousands) + "Thousand ";
                else
                    words += strones[thousands - 1] + " Thousand ";
            }

            if (hundreds > 0)
                words += strones[hundreds - 1] + " Hundred ";

            if (tens > 0)
                words += strtens[tens - 2] + " ";

            if (single > 0)
                words += strones[single - 1] + " ";

            return words;
        }
    }
}