How to change system date format

using System;
using System.Globalization;
using System.Threading;

public class DateToStringExample
{
   public static void Main()
   {
      CultureInfo currentCulture = Thread.CurrentThread.CurrentCulture;
      DateTime exampleDate = new DateTime(2008, 5, 1, 18, 32, 6);

      // Display the date using the current (en-US) culture.
      Console.WriteLine(exampleDate.ToString());

      // Change the current culture to fr-FR and display the date.
      Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("fr-FR");
      Console.WriteLine(exampleDate.ToString());

      // Change the current culture to ja-JP and display the date.
      Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture("ja-JP");
      Console.WriteLine(exampleDate.ToString());

      // Restore the original culture
      Thread.CurrentThread.CurrentCulture = currentCulture;
   }
}
// The example displays the following output to the console:
//       5/1/2008 6:32:06 PM
//       01/05/2008 18:32:06
//       2008/05/01 18:32:06