EncryptionAlgorithms.Fraction.GCD C# (CSharp) Method

        private static long GCD(long iNo1, long iNo2)
        {
            // take absolute values
            if (iNo1 < 0) iNo1 = -iNo1;
            if (iNo2 < 0) iNo2 = -iNo2;

            do
            {
                if (iNo1 < iNo2)
                {
                    long tmp = iNo1;  // swap the two operands
                    iNo1 = iNo2;
                    iNo2 = tmp;
                }
                iNo1 = iNo1 % iNo2;
            } while (iNo1 != 0);
            return iNo2;
        }