how conver number into words

public string retWord(int number)
    {

        if (number == 0) return "Zero";
        if (number == -2147483648) return "inus Two Hundred and Fourteen Crore Seventy Four Lakh Eighty Three Thousand Six Hundred and Forty Eight";
        int[] num = new int[4];
        int first = 0;
        int u, h, t;
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        if (number < 0)
        {
            sb.Append("Minus");
            number = -number;
        }
        string[] words0 = { "", "One ", "Two ", "Three", "Four ", "Five", "Six ", "Seven", "Eight ", "Nine " };
        string[] words = { "Ten", "Eleven ", "Twelve ", "Thirteen ", "Fourteen ", "Fifteen ", "Sixteen ", "Seventeen ", "Eighteen ", "Nineteen " };
        string[] words2 = { "Twenty ", "Thirty", "Forty", "Fifty ", "Sixty ", "Seventy", "Eighty", "Ninety" };
        string[] words3 = { "Thousand ", "Lakh", "Crore" };
        num[0] = number % 1000; // units
        num[1] = number / 1000;
        num[2] = number / 100000;
        num[1] = num[1] - 100 * num[2]; // thousands
        num[3] = number / 10000000; // crores
        num[2] = num[2] - 100 * num[3]; // lakhs
        for (int i = 3; i > 0; i--)
        {
            if (num[i] != 0)
            { first = i; break; }
        }

        for (int i = first; i >= 0; i--)
        {
            if (num[i] == 0) continue;
            u = num[i] % 10; // ones
            t = num[i] / 10;
            h = num[i] / 100; // hundreds
            t = t - 10 * h; // tens
            if (h > 0) sb.Append(words0[h] + "Hundred ");
            if (u > 0 || t > 0)
            {
                if (h > 0 || i == 0) sb.Append("and ");
                if (t == 0)
                    sb.Append(words0[u]);
                else if (t == 1)
                    sb.Append(words[u]);
                else
                    sb.Append(words2[t - 2] + words0[u]);
            }
            if (i != 0) sb.Append(words3[i - 1]);
        }
        return sb.ToString().TrimEnd();

    }