/*

    Thomas Wehrmeyer

    09/24/2021

*/

using System;

public class Program

{

    public static void Main()

    {

        int userYear = 0;

        string userRepeat = "";

        do 

        {

            Console.WriteLine("Enter a year after 1600:");

            userYear = int.Parse(Console.ReadLine());

            if (userYear <= 1600)

            {

                Console.WriteLine("Not a valid year after 1600. Try again");

                continue;

            }

            //Test if leap year

            if (userYear % 4 == 0 && userYear % 100 != 0 ||

                userYear % 4 == 0 && userYear % 100 == 0 && userYear % 400 == 0)

            {

                Console.WriteLine(userYear + " is a leap year!");

            }

            else

            {

                Console.WriteLine(userYear + " is not a leap year!");

                //Find next leap year

                int nextLeap = userYear + 1;

                nextLeap += (nextLeap % 4);

                bool isLeapYear = false;

                do

                {

                    if (nextLeap % 4 == 0 && nextLeap % 100 != 0 ||

                        nextLeap % 4 == 0 && nextLeap % 100 == 0 && nextLeap % 400 == 0)

                    {

                        isLeapYear = true;

                        Console.WriteLine("The next leap year is " + nextLeap);

                    }

                    else

                    {

                        nextLeap += 4;

                    }

                } while (isLeapYear != true);

            }

            Console.WriteLine("Would you like to try another year?");

            userRepeat = Console.ReadLine().ToLower();

        } while (userRepeat != "no");

    }

};