When I build thi projecct I get errors of LinkedList as undefined thing, plz guide me
using System;
using System.Text;
using System.Collections.Generic;
public class Example
{
public static void Main()
{
string[] words =
{ "the", "fox", "jumped", "over", "the", "dog" };
LinkedList<string> sentence = new LinkedList<string>(words);
Display(sentence, "The linked list values:");
Console.WriteLine("sentence.Contains(\"jumped\") = {0}",
sentence.Contains("jumped"));
sentence.AddFirst("today");
Display(sentence, "Test 1: Add 'today' to beginning of the list:");
LinkedListNode<string> mark1 = sentence.First;
sentence.RemoveFirst();
sentence.AddLast(mark1);
Display(sentence, "Test 2: Move first node to be last node:");
sentence.RemoveLast();
sentence.AddLast("yesterday");
Display(sentence, "Test 3: Change the last node to 'yesterday':");
mark1 = sentence.Last;
sentence.RemoveLast();
sentence.AddFirst(mark1);
Display(sentence, "Test 4: Move last node to be first node:");
sentence.RemoveFirst();
LinkedListNode<string> current = sentence.FindLast("the");
IndicateNode(current, "Test 5: Indicate last occurence of 'the':");
sentence.AddAfter(current, "old");
sentence.AddAfter(current, "lazy");
IndicateNode(current, "Test 6: Add 'lazy' and 'old' after 'the':");
current = sentence.Find("fox");
IndicateNode(current, "Test 7: Indicate the 'fox' node:");
sentence.AddBefore(current, "quick");
sentence.AddBefore(current, "brown");
IndicateNode(current, "Test 8: Add 'quick' and 'brown' before 'fox':");
mark1 = current;
LinkedListNode<string> mark2 = current.Previous;
current = sentence.Find("dog");
IndicateNode(current, "Test 9: Indicate the 'dog' node:");
Console.WriteLine("Test 10: Throw exception by adding node (fox) already in the list:");
try
{
sentence.AddBefore(current, mark1);
}
catch (InvalidOperationException ex)
{
Console.WriteLine("Exception message: {0}", ex.Message);
}
Console.WriteLine();
sentence.Remove(mark1);
sentence.AddBefore(current, mark1);
IndicateNode(current, "Test 11: Move a referenced node (fox) before the current node (dog):");
sentence.Remove(current);
IndicateNode(current, "Test 12: Remove current node (dog) and attempt to indicate it:");
sentence.AddAfter(mark2, current);
IndicateNode(current, "Test 13: Add node removed in test 11 after a referenced node (brown):");
sentence.Remove("old");
Display(sentence, "Test 14: Remove node that has the value 'old':");
sentence.RemoveLast();
ICollection<string> icoll = sentence;
icoll.Add("rhinoceros");
Display(sentence, "Test 15: Remove last node, cast to ICollection, and add 'rhinoceros':");
Console.WriteLine("Test 16: Copy the list to an array:");
string[] sArray = new string[sentence.Count];
sentence.CopyTo(sArray, 0);
foreach (string s in sArray)
{
Console.WriteLine(s);
}
sentence.Clear();
Console.WriteLine();
Console.WriteLine("Test 17: Clear linked list. Contains 'jumped' = {0}",
sentence.Contains("jumped"));
Console.ReadLine();
}
private static void Display(LinkedList<string> words, string test)
{
Console.WriteLine(test);
foreach (string word in words)
{
Console.Write(word + " ");
}
Console.WriteLine();
Console.WriteLine();
}
private static void IndicateNode(LinkedListNode<string> node, string test)
{
Console.WriteLine(test);
if (node.List == null)
{
Console.WriteLine("Node '{0}' is not in the list.\n",
node.Value);
return;
}
StringBuilder result = new StringBuilder("(" + node.Value + ")");
LinkedListNode<string> nodeP = node.Previous;
while (nodeP != null)
{
result.Insert(0, nodeP.Value + " ");
nodeP = nodeP.Previous;
}
node = node.Next;
while (node != null)
{
result.Append(" " + node.Value);
node = node.Next;
}
Console.WriteLine(result);
Console.WriteLine();
}
}
//This code example produces the following output:
//
//The linked list values:
//the fox jumped over the dog
//Test 1: Add 'today' to beginning of the list:
//today the fox jumped over the dog
//Test 2: Move first node to be last node:
//the fox jumped over the dog today
//Test 3: Change the last node to 'yesterday':
//the fox jumped over the dog yesterday
//Test 4: Move last node to be first node:
//yesterday the fox jumped over the dog
//Test 5: Indicate last occurence of 'the':
//the fox jumped over (the) dog
//Test 6: Add 'lazy' and 'old' after 'the':
//the fox jumped over (the) lazy old dog
//Test 7: Indicate the 'fox' node:
//the (fox) jumped over the lazy old dog
//Test 8: Add 'quick' and 'brown' before 'fox':
//the quick brown (fox) jumped over the lazy old dog
//Test 9: Indicate the 'dog' node:
//the quick brown fox jumped over the lazy old (dog)
//Test 10: Throw exception by adding node (fox) already in the list:
//Exception message: The LinkedList node belongs a LinkedList.
//Test 11: Move a referenced node (fox) before the current node (dog):
//the quick brown jumped over the lazy old fox (dog)
//Test 12: Remove current node (dog) and attempt to indicate it:
//Node 'dog' is not in the list.
//Test 13: Add node removed in test 11 after a referenced node (brown):
//the quick brown (dog) jumped over the lazy old fox
//Test 14: Remove node that has the value 'old':
//the quick brown dog jumped over the lazy fox
//Test 15: Remove last node, cast to ICollection, and add 'rhinoceros':
//the quick brown dog jumped over the lazy rhinoceros
//Test 16: Copy the list to an array:
//the
//quick
//brown
//dog
//jumped
//over
//the
//lazy
//rhinoceros
//Test 17: Clear linked list. Contains 'jumped' = False
//