using System;

     using System.Collections;

     abstract class Component

     {

         protected string strName;

         public Component(string name)

         {

             strName = name;

         }

         abstract public void Add(Component c);

         public abstract void DumpContents();

         // other operations for delete, get, etc.

     }

     class Composite : Component

     {

         private ArrayList ComponentList = new ArrayList();

         public Composite(string s) : base(s) {}

         override public void Add(Component c)

         {

             ComponentList.Add(c);

         }

         public override void DumpContents()

         {

             // First dump the name of this composite node

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

             // Then loop through children, and get then to dump their contents

             foreach (Component c in ComponentList)

             {

                 c.DumpContents();

             }

         }

     }

     class Leaf : Component

     {

         public Leaf(string s) : base(s) {}

         override public void Add(Component c)

         {

             Console.WriteLine("Cannot add to a leaf");

         }

         public override void DumpContents()

         {

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

         }

     }

     /// <summary>

     ///    Summary description for Client.

     /// </summary>

     public class Client

     {

         Component SetupTree()

         {

             // here we have to create a tree structure,

             // consisting of composites and leafs.

             Composite root = new Composite("root-composite");

             Composite parentcomposite;

             Composite composite;

             Leaf leaf;

             parentcomposite = root;

             composite = new Composite("first level - first sibling - composite");

             parentcomposite.Add(composite);

             leaf = new Leaf("first level - second sibling - leaf");

             parentcomposite.Add(leaf);

             parentcomposite = composite;

             composite = new Composite("second level - first sibling - composite");

             parentcomposite.Add(composite);

             composite = new Composite("second level - second sibling - composite");

             parentcomposite.Add(composite);

             // we will leaf the second level - first sibling empty, and start

             // populating the second level - second sibling

             parentcomposite = composite;

             leaf = new Leaf("third level - first sibling - leaf");

             parentcomposite.Add(leaf);

             leaf = new Leaf("third level - second sibling - leaf");

             parentcomposite.Add(leaf);

             composite = new Composite("third level - third sibling - composite");

             parentcomposite.Add(composite);

             return root;

         }

         public static int Main(string[] args)

         {

                Component component;

             Client c = new Client();

             component = c.SetupTree();

             component.DumpContents();

             return ;

         }

     }