using System;

public class Program

{

    public static void Main()

    {

    string choice = "y";

        while(choice != "Q" && choice != "q")

        {

        Console.WriteLine("Please input a number to know the square root up to the certain number.");

        error:

        string n = Console.ReadLine();

        double number;

        double root;

        if (double.TryParse(n, out number))

            {

                double i = 1;

                do 

                {

                root = Math.Sqrt(i);

                 if (number >= 1)

                 {

                    Console.WriteLine("The square root of " +i+ " is " +root.ToString("##.###")+ ".");

                     i++;

                 }

                else if (number == 0)

                { 

                    Console.WriteLine("Please enter a number from 1 to anything above.");

                    goto error;

                }

                 else if (number < 1)

                 {

                  Console.WriteLine("Please enter a positive number.");

                  goto error;

                 }

            }

                while (i <= number);

        Console.WriteLine("Please enter q to quit and any other key to continue.");

        choice = Console.ReadLine();

        }

​

            else 

            {

                Console.WriteLine("Please enter a positive number.");

                goto error;

            }

        }

    }

}