NP91 Clone() method

Hi Guys

 

NP91 Clone() method

 

Following program is producing same result even if following codes are commented out. What is the significant of the codes. 

 

copyPtDesc.petName = this.desc.petName;

copyPtDesc.creationDate = this.desc.creationDate;

 

Anyone knows please explain the reason.

 

Thank you

 

using System;

 

namespace ObjClone

{

   #region The point description type

   // This class describes a point.

   public class PointDesc

   {

      // Public for easy access.

      public string petName;

      public DateTime creationDate;

 

      public PointDesc(string petName)

      {

         this.petName = petName;

 

         // Inject a time lag to get different times.

         System.Threading.Thread.Sleep(2000);

         creationDate = DateTime.Now;

      }

 

      public string CreationTime()

      {

         // Return a string with date/time information.

         return creationDate.ToString();

      }

   }

   #endregion

 

   #region Cloneable point type

   // The Point class supports deep copy semantics ala ICloneable.

   public class Point : ICloneable

   {

      // State data.

      public int x, y;

      public PointDesc desc;

 

      // Ctors.

      public Point() { }

     

      public Point(int x, int y, string petname)

      {

         this.x = x;

         this.y = y;

         desc = new PointDesc(petname);

      }

 

      // The sole method of ICloneable.

      public object Clone()

      {

         // return this.MemberwiseClone();

 

         // Now we need to adjust for the PointDesc type.

         Point copyPt = new Point();

         copyPt.x = this.x;

         copyPt.y = this.y;

 

         PointDesc copyPtDesc = new PointDesc(this.desc.petName);

         copyPtDesc.petName = this.desc.petName;

         copyPtDesc.creationDate = this.desc.creationDate;

 

         copyPt.desc = copyPtDesc;

         return copyPt;

 

      }

 

      // Override Object.ToString().

      public override string ToString()

      {

         return "X: " + x + " Y: " + y +

            " PetName: " + desc.petName +

            " Time of creation: " + desc.CreationTime();

      }

   }

   #endregion

 

   public class CloneApp

   {

      public static int Main(string[] args)

      {

         // Two references to same object!

         Console.WriteLine("***** Assigning points *****");

         Point p1 = new Point(50, 50, "Fred");

         Point p2 = p1;

         p2.x = 0;

 

         // Print each obj.

         Console.WriteLine("p1 is {0}", p1);

         Console.WriteLine("p2 is {0}\n", p2);

 

         // Now Clone object.

         Console.WriteLine("***** Cloning p3 and holding in p4 *****");

         Point p3 = new Point(100, 100, "Jane");

         Point p4 = (Point)p3.Clone();

 

         Console.WriteLine("-> Before pet name modification");

         Console.WriteLine("p3: {0}", p3);

         Console.WriteLine("p4: {0}", p4);

 

         p4.desc.petName = "XXXXX";

 

         Console.WriteLine("\n-> After pet name modification");

         Console.WriteLine("p3: {0}", p3);

         Console.WriteLine("p4: {0}\n", p4);

         return 0;

      }

   }

}

/*

***** Assigning points *****

p1 is X: 0 Y: 50 PetName: Fred Time of creation: 3/27/2008 1:34:12 PM

p2 is X: 0 Y: 50 PetName: Fred Time of creation: 3/27/2008 1:34:12 PM

 

***** Cloning p3 and holding in p4 *****

-> Before pet name modification

p3: X: 100 Y: 100 PetName: Jane Time of creation: 3/27/2008 1:34:14 PM

p4: X: 100 Y: 100 PetName: Jane Time of creation: 3/27/2008 1:34:14 PM

 

-> After pet name modification

p3: X: 100 Y: 100 PetName: Jane Time of creation: 3/27/2008 1:34:14 PM

p4: X: 100 Y: 100 PetName: XXXXX Time of creation: 3/27/2008 1:34:14 PM

*/