using System;

using System.Globalization;

using System.Collections.Generic;

using System.Collections.ObjectModel;

//using System.

public class Program

{

    public static void Main()

    {

        //Console.WriteLine(DateTime.Now.AddMonths(1).ToString("MMddyy"));

        //Console.WriteLine(DaylightTime.GetDaylightChanges(2025));

        ShowStartAndEndDates();

        //return;

        //TimeZoneInfo centralTZ = TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time");

​

        /*

        DateTime date = DateTime.Now;

            //TimeZoneInfo.ConvertTimeBySystemTimeZoneId(DateTime.Now,"Central Standard Time");

        DateTime threshold = DateTime.Parse("2025-03-10 00:00:00");

        //date = //DateTime.SpecifyKind(date, DateTimeKind.Unspecified);

        //Console.WriteLine(date.Kind);

        while(date < threshold)

        {

            date = date.AddMinutes(30);

            Console.WriteLine(date.ToString("s") + " Is Daylight Savings? " + date.IsDaylightSavingTime());

        }*/

    }

    private enum WeekOfMonth 

{

   First = 1,

   Second = 2,

   Third = 3,

   Fourth = 4,

   Last = 5,

}

​

private static void ShowStartAndEndDates()

{

   // Get all time zones from system

    List<TimeZoneInfo> timeZones = new List<TimeZoneInfo>();

    timeZones.Add(TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time"));

   string[] monthNames = CultureInfo.CurrentCulture.DateTimeFormat.MonthNames;

   // Get each time zone

   foreach (TimeZoneInfo timeZone in timeZones)

   {

      TimeZoneInfo.AdjustmentRule[] adjustments = timeZone.GetAdjustmentRules();

       Console.WriteLine("{0} rules found!",adjustments.Length);

      // Display message for time zones with no adjustments

      if (adjustments.Length == 0)

      {

         Console.WriteLine("{0} has no adjustment rules", timeZone.StandardName);

      }   

      else

      {

         // Handle time zones with 1 or 2+ adjustments differently

         bool showCount = false;

         int ctr = 0;

         string spacer = "";

         Console.WriteLine("{0} Adjustment rules", timeZone.StandardName);

         if (adjustments.Length > 1)

         {

            showCount = true;

            spacer = "   ";

         }   

         // Iterate adjustment rules

         foreach (TimeZoneInfo.AdjustmentRule adjustment in adjustments)

         {

            if (showCount)

            { 

               Console.WriteLine("   Adjustment rule #{0}", ctr+1);

               ctr++;

            }

            // Display general adjustment information

            Console.WriteLine("{0}   Start Date: {1:D}", spacer, adjustment.DateStart);

            Console.WriteLine("{0}   End Date: {1:D}", spacer, adjustment.DateEnd);

            Console.WriteLine("{0}   Time Change: {1}:{2:00} hours", spacer, 

                              adjustment.DaylightDelta.Hours, adjustment.DaylightDelta.Minutes);

            // Get transition start information

            TimeZoneInfo.TransitionTime transitionStart = adjustment.DaylightTransitionStart;

            Console.Write("{0}   Annual Start: ", spacer);

            if (transitionStart.IsFixedDateRule)

            {

               Console.WriteLine("On {0} {1} at {2:t}", 

                                 monthNames[transitionStart.Month - 1], 

                                 transitionStart.Day, 

                                 transitionStart.TimeOfDay);

            }

            else

            {

               Console.WriteLine("The {0} {1} of {2} at {3:t}", 

                                 ((WeekOfMonth)transitionStart.Week).ToString(), 

                                 transitionStart.DayOfWeek.ToString(), 

                                 monthNames[transitionStart.Month - 1], 

                                 transitionStart.TimeOfDay);

            }

            // Get transition end information

            TimeZoneInfo.TransitionTime transitionEnd = adjustment.DaylightTransitionEnd;

            Console.Write("{0}   Annual End: ", spacer);

            if (transitionEnd.IsFixedDateRule)

            {

               Console.WriteLine("On {0} {1} at {2:t}", 

                                 monthNames[transitionEnd.Month - 1], 

                                 transitionEnd.Day, 

                                 transitionEnd.TimeOfDay);

            }

            else

            {

               Console.WriteLine("The {0} {1} of {2} at {3:t}", 

                                 ((WeekOfMonth)transitionEnd.Week).ToString(), 

                                 transitionEnd.DayOfWeek.ToString(), 

                                 monthNames[transitionEnd.Month - 1], 

                                 transitionEnd.TimeOfDay);

            }

         }

      }   

      Console.WriteLine();

   } 

}

}