public void multiply(string number)
        {
            BigNumberFacilitator result = new BigNumberFacilitator("0");

            for (int idx = number.Length, offset = 0; --idx != -1; ++offset)
            {
                int    digit = number[idx] - '0';
                string product;
                switch (digit)
                {
                case 0:
                    product = "0";
                    break;

                case 1:
                    product = d_number;
                    break;

                default:
                    product = multiplyNumber(d_number, digit, 0,
                                             d_number.Length - 1);
                    break;
                }
                if (product != "0")
                {
                    product = appendZeros(product, offset);
                }

                result.add(product);
            }
            d_number = result.getNumber();
        }
        static private string hexToDec(string hex)
        {
            BigNumberFacilitator factor = new BigNumberFacilitator("1");
            BigNumberFacilitator result = new BigNumberFacilitator("0");

            while (hex.Length != 0)
            {
                int num = hexToInt(hex[hex.Length - 1]);
                hex = hex.Remove(hex.Length - 1);
                BigNumberFacilitator temp =
                    new BigNumberFacilitator(num.ToString());

                temp.multiply(factor.getNumber());
                result.add(temp.getNumber());

                factor.multiply("16");
            }
            return(result.getNumber());
        }