using System;

public class Program

{

    public static void Main()

    {

        start:

        Console.WriteLine("Did you know leap year was created in 1582");

        Console.WriteLine("This is due to an year not exactly being 365 years");

        Console.WriteLine("Every year is technically 365.25 days long so in 4 years 1 full day is added to a year");

        Console.WriteLine("This is known as the leap year");

        Console.WriteLine("Please enter a year more than 1582");

        begin:

        string answer = Console.ReadLine();

        ulong y;

        if(ulong.TryParse(answer,out y))

        {

            if(y>=1582 && y<3000 &&y%4==0)

            {

                Console.Clear();

                    Console.WriteLine("This is a leap year");

             if(y==2020)

                {

                Console.WriteLine("Did you know covid 19 (a virus) shut down many places leading to a mass lockdown in 2020");

                }

            }

            else if(y==2021)

               {Console.WriteLine("This is not a leap year but did you know...");

                Console.WriteLine("The border between Qatar and Saudi Arabia opened up on January 4");}

            else if(y>=1582 && y<3000 && y%4!=0)

                {Console.WriteLine("This is not a leap year");}

        else if(y<1582)

        {

            Console.Clear();

            Console.WriteLine("Please enter a more recent year. The change for leap year was made in 1582. There was no leap years before this.");

            goto begin;

​

        }

        else if(y>3000)

        {

            Console.Clear();

    Console.WriteLine("Please don't go too far in the future. Please enter a year a little bit lower.");

            goto begin;}

        else if(y%4!=0)

        {

            Console.Clear();

            Console.WriteLine("This is not a leap year. This is a common year");

        }

        }

        else 

        {

            Console.Clear();

            Console.WriteLine("Error, please enter a positive value/integer.");

            goto begin;

        }

    Console.WriteLine("Would you like to try another leap year that is greater than 1582 and less than 3000");

            string choice =Console.ReadLine();

        if(choice=="y"||choice=="Y")

        {

            Console.Clear();

            goto start;}

        else if(choice=="n"||choice=="N")

        {

            Console.Clear();

            Console.WriteLine("Thak you for using the code");}

        }

    }

​

​