using System;

namespace SquareRootCalculator
{
    class Program
    {
        static void Main(string[] args)
        {
                Console.WriteLine("Please enter a number to find the square root of and then press \'Enter\': ");
                Console.WriteLine("________________________________________________\n");
                bool detector = false;
                double x;
                double userInput = 0;
                while (detector == false)
                {
                    if (!double.TryParse(Console.ReadLine(), out x))
                    {
                        Console.WriteLine("The square root calculator needs a number greater than zero.\n");
                        Console.WriteLine("Please enter a number to find the square root of and then press \'Enter\': ");
                    }
                    else if (x < 0)
                    {
                        Console.WriteLine("The square root calculator needs a number greater than zero.\n");
                        Console.WriteLine("Please enter a number to find the square root of and then press \'Enter\': ");
                    }
                    else
                    {
                        detector = true;
                        userInput = Convert.ToDouble(x);
                    }
                }

                double y = userInput * (userInput * .1);
                double answer;
                for (int i = 0; i < 100; i++)
                {
                    answer = 0.5 * (y + (userInput / y));
                    // takes output and causes the next iteration of the formula to use the output to calculate the new value
                    y = answer;
                }
                Console.WriteLine("\nYour answer is: " + "{0:0.#######}", y);
                Console.ReadKey();
        }
    }
}