6.10Loops_EuclideanAlgorithm

// Write a program that calculates the greatest common divisor (GCD) of given two integers a and b. Use the Euclidean algorithm (find it in Internet).

namespace _17.CalculateGCD
{
    using System;

    public class EuclideanAlgorithm
    {
        public static void Main(string[] args)
        {
            checked
            {
                Console.Write("Enter a Integer number: ");
                int firstNum = int.Parse(Console.ReadLine());
                int secondNum;
                do
                {
                    Console.Write("Enter other Integer number, different from the First: ");
                }
                while (!int.TryParse(Console.ReadLine(), out secondNum) || secondNum == firstNum);

                int numA = Math.Abs(firstNum);
                int numB = Math.Abs(secondNum);
                if (numB > numA)
                {
                    int numC = numA;
                    numA = numB;
                    numB = numC;
                }

                while (numB > 0)
                {
                    int remainder = numA % numB;
                    numA = numB;
                    numB = remainder;
                }

                int gcd = numA;
                Console.WriteLine("The Greatest Common Divisor of ({0}, {1}) is: {2} !", firstNum, secondNum, gcd);
            }
        }
    }
}