double linkedlist in c#

C#/DoubleLinkedList.cs

@@ -1,38 +1,100 @@
-class DoubleLinkedList<T>
+public static void Main()
 {
- private T value;
- private LinkedList<T> next;
- private LinkedList<T> prev;
-
- public DoubleLinkedList(LinkedList<T> prev, T value, LinkedList<T> next) {
- SetPrev(prev);
- SetValue(value);
- SetNext(next);
- }
-
- public DoubleLinkedList(T value) : this(null, value, null){}
-
- public LinkedList<T> GetPrev() {
- return prev;
- }
-
- public T GetValue() {
- return value;
- }
-
- public LinkedList<T> GetNext() {
- return next;
- }
-
- public void SetPrev(LinkedList<T> prev) {
- this.prev = prev;
- }
-
- public void SetValue(T value) {
- this.value = value;
- }
-
- public void SetNext(LinkedList<T> next) {
- this.next = next;
- }
-}
+ DoubleLinkedList list = new DoubleLinkedList();
+ list.Insert("1");
+ list.Insert("2");
+ list.Insert("3");
+
+ DoubleLink link4 = list.Insert("4");
+ list.Insert("5");
+ Console.WriteLine("List: " + list);
+
+ list.InsertAfter(link4, "[4a]");
+ Console.WriteLine("List: " + list);
+ Console.Read();
+}
+
+public class DoubleLink
+{
+ public string Title { get; set; }
+ public DoubleLink PreviousLink { get; set; }
+ public DoubleLink NextLink { get; set; }
+
+ public DoubleLink(string title)
+ {
+ Title = title;
+ }
+
+ public override string ToString()
+ {
+ return Title;
+ }
+}
+
+public class DoubleLinkedList
+{
+ private DoubleLink _first;
+ public bool IsEmpty
+ {
+ get
+ {
+ return _first == null;
+ }
+ }
+ public DoubleLinkedList()
+ {
+ _first = null;
+ }
+
+ public DoubleLink Insert(string title)
+ {
+ // Creates a link, sets its link to the first item and then makes this the first item in the list.
+ DoubleLink link = new DoubleLink(title);
+ link.NextLink = _first;
+ if (_first != null)
+ _first.PreviousLink = link;
+ _first = link;
+ return link;
+ }
+
+ public DoubleLink Delete()
+ {
+ // Gets the first item, and sets it to be the one it is linked to
+ DoubleLink temp = _first;
+ if (_first != null)
+ {
+ _first = _first.NextLink;
+ if (_first != null)
+ _first.PreviousLink = null;
+ }
+ return temp;
+ }
+
+ public override string ToString()
+ {
+ DoubleLink currentLink = _first;
+ StringBuilder builder = new StringBuilder();
+ while (currentLink != null)
+ {
+ builder.Append(currentLink);
+ currentLink = currentLink.NextLink;
+ }
+ return builder.ToString();
+ }
+
+ ///// New operations
+ public void InsertAfter(DoubleLink link, string title)
+ {
+ if (link == null || string.IsNullOrEmpty(title))
+ return;
+ DoubleLink newLink = new DoubleLink(title);
+ newLink.PreviousLink = link;
+ // Update the 'after' link's next reference, so its previous points to the new one
+ if (link.NextLink != null)
+ link.NextLink.PreviousLink = newLink;
+ // Steal the next link of the node, and set the after so it links to our new one
+ newLink.NextLink = link.NextLink;
+ link.NextLink = newLink;
+ }
+}
+}