// 
//  Interface example by Josh Santomieri
//  Santomieri Systems - 08/25/2006
//

using System;
using System.Collections;

/// 

/// Interface for custom lists.
/// 
public interface IMyList
{
	/// 

	/// Gets or sets the object at the index i.
	/// 
	object this[int i]
	{
		get;
		set;
	}

	/// 

	/// Gets the count of items in the list.
	/// 
	int Count
	{
		get;
	}

	/// 

	/// Allows you to add an object to the list.
	/// 
	/// The object to add to the list.
	void Add(object item);
}

/// 

/// Represents a list.
/// 
public class MyList : IMyList
{
	private ArrayList _list;

	/// 

	/// Creates a new MyList.
	/// 
	public MyList()
	{
		this._list = new ArrayList();
	}

	/// 

	/// Gets or sets the object at index i. (interface declaration)
	/// 
	public object this[int i]
	{
		get
		{
			return this._list[i];
		}
		set
		{
			this._list[i] = value;
		}
	}

	/// 

	/// Gets the count of items in the list. (interface declaration)
	/// 
	public int Count
	{
		get { return this._list.Count; }
	}

	/// 

	/// Adds an item to the list.
	/// 
	/// The item to add to the list.
	public void Add(object item)
	{
		this._list.Add(item);
	}
}

/// 

/// Represents a list #2.
/// 
public class MyList2 : IMyList
{
	private ArrayList _list;

	/// 

	/// Creates a new MyList.
	/// 
	public MyList2()
	{
		this._list = new ArrayList();
	}

	/// 

	/// Gets or sets the object at index i. (interface declaration)
	/// 
	public object this[int i]
	{
		get
		{
			return this._list[i];
		}
		set
		{
			this._list[i] = value;
		}
	}

	/// 

	/// Gets the count of items in the list. (interface declaration)
	/// 
	public int Count
	{
		get { return this._list.Count; }
	}

	/// 

	/// Adds an item to the list.
	/// 
	/// The item to add to the list.
	public void Add(object item)
	{
		this._list.Add(item);
	}
}

/// 

/// Gets information about a list...
/// 
public class ListInfo
{
	/// 

	/// Gets the count of items in a list that uses the IMyList interface
	/// 
	/// A list of type IMyList.
	/// The number of items in the list.
	public static int ItemsInList(IMyList list)
	{
		if (list == null)
		{
			throw new ArgumentNullException("list");
		}
		return list.Count;
	}
}

/// 

/// Represents the main entry point for the program.
/// 
class Program
{
	static void Main(string[] args)
	{
		// Create the new list items.
		MyList list = new MyList();
		MyList2 list2 = new MyList2();

		// Populate the lists
		list.Add("test1");
		list.Add("test2");

		list2.Add("test1");

		// Using one function, write out the number of items in the lists...
		// Output should be: 
		//    Items In MyList: 2
		//    Items In MyList2: 1
		Console.WriteLine("Items In MyList: " + ListInfo.ItemsInList(list));
		Console.WriteLine("Items In MyList2: " + ListInfo.ItemsInList(list2));
	}
}