Comparison of Implementations of the Euclidean algorithm

using System;
using System.Numerics;
using System.Diagnostics;

namespace GreatestCommonDivisorEuclid
{
    class GreatestCommonDivisorEuclid
    {
        static BigInteger GcdMine(BigInteger num1, BigInteger num2)
        {
            BigInteger temp;

            if (num1 > num2)
            {
                while (num1 % num2 != 0)
                {
                    temp = num2;
                    num2 = num1 % num2;
                    num1 = temp;
                }
                return num2;
            }
            else
            {
                while (num2 % num1 != 0)
                {
                    temp = num1;
                    num1 = num2 % num1;
                    num2 = temp;
                }
                return num1;
            }
        }

        static BigInteger GcdRecursion(BigInteger num1, BigInteger num2)
        {
            if (num2 == 0)
            {
                return num1;
            }
            else
            {
                return GcdRecursion(num2, num1 % num2);
            }
        }

        static BigInteger GcdIterativeDivision(BigInteger num1, BigInteger num2)
        {
            while (num1 != 0 && num2 != 0)
            {
                if (num1 > num2)
                {
                    num1 %= num2;
                }
                else
                {
                    num2 %= num1;
                }
            }

            if (num1 == 0)
            {
                return num2;
            }
            else
            {
                return num1;
            }
        }

        static BigInteger GcdIterativeSubtraction(BigInteger num1, BigInteger num2)
        {
            while (num1 != 0 && num2 != 0)
            {
                if (num1 > num2)
                    num1 -= num2;
                else
                    num2 -= num1;
            }

            if (num1 > num2)
            {
                return num1;
            }
            else
            {
                return num2;
            }
        }

        static void Main(string[] args)
        {
            //bool success;
            //string toBeParsed;
            BigInteger firstNumber = 14234298148921987940, secondNumber = 213484887418;
            BigInteger gcd;

            //do
            //{
            //    Console.Clear();
            //    Console.Write("Enter first number: ");
            //    toBeParsed = Console.ReadLine();
            //    success = BigInteger.TryParse(toBeParsed, out firstNumber);
            //}
            //while ((!success) || (firstNumber < 1));

            //do
            //{
            //    Console.Clear();
            //    Console.WriteLine("Enter first number: {0}", firstNumber);
            //    Console.Write("Enter second number: ");
            //    toBeParsed = Console.ReadLine();
            //    success = BigInteger.TryParse(toBeParsed, out secondNumber);
            //}
            //while ((!success) || (secondNumber < 1));

            Stopwatch timer = new Stopwatch();

            timer.Start();
            gcd = GcdMine(firstNumber, secondNumber);
            timer.Stop();
            Console.WriteLine("GCD is {0}", gcd);
            Console.WriteLine("Elapsed System Clock Ticks: " + timer.ElapsedTicks);

            timer.Reset();
            timer.Start();
            gcd = GcdRecursion(firstNumber, secondNumber);
            timer.Stop();
            Console.WriteLine("GCD (recursion algorithm) is {0}", gcd);
            Console.WriteLine("Elapsed System Clock Ticks: " + timer.ElapsedTicks);

            timer.Reset();
            timer.Start();
            gcd = GcdIterativeDivision(firstNumber, secondNumber);
            timer.Stop();
            Console.WriteLine("GCD (iterative algorithm with division) is {0}", gcd);
            Console.WriteLine("Elapsed System Clock Ticks: " + timer.ElapsedTicks);

            timer.Reset();
            timer.Start();
            gcd = GcdIterativeSubtraction(firstNumber, secondNumber);
            timer.Stop();
            Console.WriteLine("GCD (iterative algorithm with subtraction) is {0}", gcd);
            Console.WriteLine("Elapsed System Clock Ticks: " + timer.ElapsedTicks);
        }
    }
}