//引入命名空间
using System;
using System.Text;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create the link list.
        string[] words =
            { "the", "fox", "jumps", "over", "the", "dog" };
        LinkedList<string> sentence = new LinkedList<string>(words);
        Display(sentence, "The linked list values:");
        Console.WriteLine("sentence.Contains(\"jumps\") = {0}",
            sentence.Contains("jumps"));

        // Add the word 'today' to the beginning of the linked list.
        sentence.AddFirst("today");
        Display(sentence, "Test 1: Add 'today' to beginning of the list:");

        // Move the first node to be the last node.
        LinkedListNode<string> mark1 = sentence.First;
        sentence.RemoveFirst();
        sentence.AddLast(mark1);
        Display(sentence, "Test 2: Move first node to be last node:");

        // Change the last node to 'yesterday'.
        sentence.RemoveLast();
        sentence.AddLast("yesterday");
        Display(sentence, "Test 3: Change the last node to 'yesterday':");

        // Move the last node to be the first node.
        mark1 = sentence.Last;
        sentence.RemoveLast();
        sentence.AddFirst(mark1);
        Display(sentence, "Test 4: Move last node to be first node:");

        // Indicate the last occurence of 'the'.
        sentence.RemoveFirst();
        LinkedListNode<string> current = sentence.FindLast("the");
        IndicateNode(current, "Test 5: Indicate last occurence of 'the':");

        // Add 'lazy' and 'old' after 'the' (the LinkedListNode named current).
        sentence.AddAfter(current, "old");
        sentence.AddAfter(current, "lazy");
        IndicateNode(current, "Test 6: Add 'lazy' and 'old' after 'the':");

        // Indicate 'fox' node.
        current = sentence.Find("fox");
        IndicateNode(current, "Test 7: Indicate the 'fox' node:");

        // Add 'quick' and 'brown' before 'fox':
        sentence.AddBefore(current, "quick");
        sentence.AddBefore(current, "brown");
        IndicateNode(current, "Test 8: Add 'quick' and 'brown' before 'fox':");

        // Keep a reference to the current node, 'fox',
        // and to the previous node in the list. Indicate the 'dog' node.
        mark1 = current;
        LinkedListNode<string> mark2 = current.Previous;
        current = sentence.Find("dog");
        IndicateNode(current, "Test 9: Indicate the 'dog' node:");

        // The AddBefore method throws an InvalidOperationException
        // if you try to add a node that already belongs to a list.
        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();

        // Remove the node referred to by mark1, and then add it
        // before the node referred to by current.
        // Indicate the node referred to by current.
        sentence.Remove(mark1);
        sentence.AddBefore(current, mark1);
        IndicateNode(current, "Test 11: Move a referenced node (fox) before the current node (dog):");

        // Remove the node referred to by current.
        sentence.Remove(current);
        IndicateNode(current, "Test 12: Remove current node (dog) and attempt to indicate it:");

        // Add the node after the node referred to by mark2.
        sentence.AddAfter(mark2, current);
        IndicateNode(current, "Test 13: Add node removed in test 11 after a referenced node (brown):");

        // The Remove method finds and removes the
        // first node that that has the specified value.
        sentence.Remove("old");
        Display(sentence, "Test 14: Remove node that has the value 'old':");

        // When the linked list is cast to ICollection(Of String),
        // the Add method adds a node to the end of the list.
        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:");
        // Create an array with the same number of
        // elements as the inked list.
        string[] sArray = new string[sentence.Count];
        sentence.CopyTo(sArray, 0);

        foreach (string s in sArray)
        {
            Console.WriteLine(s);
        }

        // Release all the nodes.
        sentence.Clear();

        Console.WriteLine();
        Console.WriteLine("Test 17: Clear linked list. Contains 'jumps' = {0}",
            sentence.Contains("jumps"));

        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();
    }
}