Class Interface C#

/*
Learning C# 
by Jesse Liberty
Publisher: O'Reilly 
ISBN: 0596003765
*/
 using System;
 namespace Properties
 {
     class Time
     {
         // private member variables
         private int year;
         private int month;
         private int date;
         private int hour;
         private int minute;
         private int second;
         // create a property
         public int Hour
         {
             get
             {
                 return hour;
             }
             set
             {
                 hour = value;
             }
         }
         // public accessor methods
         public void DisplayCurrentTime()
         {
             System.Console.WriteLine(
                 "Time: {0}/{1}/{2} {3}:{4}:{5}",
                 month, date, year, hour, minute, second);
         }
         // constructors
         public Time(System.DateTime dt)
         {
             year =      dt.Year;
             month =     dt.Month;
             date =      dt.Day;
             hour =      dt.Hour;
             minute =    dt.Minute;
             second =    dt.Second;
         }
    }
    public class PropertiesTester
    {
       public void Run()
       {
           System.DateTime currentTime = System.DateTime.Now;
           Time t = new Time(currentTime);
           t.DisplayCurrentTime();
           // access the hour to a local variable
           int theHour = t.Hour;
           // display it
           System.Console.WriteLine("Retrieved the hour: {0}",
               theHour);
           // increment it
           theHour++;
           // reassign the incremented value back through
           // the property
           t.Hour = theHour;
           // display the property
           System.Console.WriteLine("Updated the hour: {0}", t.Hour);
       }
       [STAThread]
       static void Main()
       {
          PropertiesTester t = new PropertiesTester();
          t.Run();
       }
    }
 }