C# 0 The Complete Reference

PART II

C h a p t e r   2 4 :  

C o l l e c t i o n s ,   E n u m e r a t o r s ,   a n d   I t e r a t o r s    

785

Here is an example that demonstrates the 

LinkedList

 class:

// Demonstrate LinkedList.

using System;

using System.Collections.Generic;

class GenLinkedListDemo {

  static void Main() {

    // Create a linked list.

    LinkedList ll = new LinkedList();

    Console.WriteLine("Initial number of elements: " +

                       ll.Count);

    Console.WriteLine();

    Console.WriteLine("Adding 5 elements.");

    // Add elements to the linked list

    ll.AddFirst('A');

    ll.AddFirst('B');

    ll.AddFirst('C');

    ll.AddFirst('D');

    ll.AddFirst('E');

    Console.WriteLine("Number of elements: " +

                       ll.Count);

    // Display the linked list by manually walking

    // through the list.

    LinkedListNode node;

    Console.Write("Display contents by following links: ");

    for(node = ll.First; node != null; node = node.Next)

      Console.Write(node.Value + " ");

    Console.WriteLine("\n");

    //Display the linked list by use of a foreach loop.

    Console.Write("Display contents with foreach loop: ");

    foreach(char ch in ll)

      Console.Write(ch + " ");

    Console.WriteLine("\n");

public void Remove(LinkedList 

n

)

Removes the node that matches 

n.

 Throws an 

InvalidOperationException

 if 

n

 is not in the list.

public void RemoveFirst( )

Removes the first node in the list.

public void RemoveLast( )

Removes the last node in the list.

T

ABLE

 24-15 

A Sampling of Methods Defi ned by 

LinkedList

(continued)

Method

Description

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786

 

P a r t   I I :  

E x p l o r i n g   t h e   C #   L i b r a r y

    // Display the list backward by manually walking

    // from last to first.

    Console.Write("Follow links backwards: ");

      for(node = ll.Last; node != null; node = node.Previous)

      Console.Write(node.Value + " ");

    Console.WriteLine("\n");

    // Remove two elements.

    Console.WriteLine("Removing 2 elements.");

    // Remove elements from the linked list.

    ll.Remove('C');

    ll.Remove('A');

    Console.WriteLine("Number of elements: " +

                       ll.Count);

    // Use foreach loop to display the modified list.

    Console.Write("Contents after deletion: ");

    foreach(char ch in ll)

      Console.Write(ch + " ");

    Console.WriteLine("\n");

    // Add three elements to the end of the list.

    ll.AddLast('X');

    ll.AddLast('Y');

    ll.AddLast('Z');

    Console.Write("Contents after addition to end: ");

    foreach(char ch in ll)

      Console.Write(ch + " ");

    Console.WriteLine("\n");

  }

}

Here is the output:

Initial number of elements: 0

Adding 5 elements.

Number of elements: 5

Display contents by following links: E D C B A

Display contents with foreach loop: E D C B A

Follow links backwards: A B C D E

Removing 2 elements.

Number of elements: 3

Contents after deletion: E D B

Contents after addition to end: E D B X Y Z

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