Bugs fixed on Delete and Insert Methods

C#/Datastructures/DoublyLinkedList.cs

@@ -93,8 +93,8 @@ namespace C_.Datastructures
 
         public void Insert(int index, T value)
         {
-            if (index > Count) throw new System.Exception("Error! Index outside of Bounds");
             Count++;
+            if (index > Count || index < 0) throw new System.Exception("Error! Index outside of Bounds");
 
             //Set head to new item if list is empty
             if (index == 0 || Head == null)
@@ -104,6 +104,12 @@ namespace C_.Datastructures
                 return;
             }
 
+            //Set tail to new item if index is the end
+            if (index == Count)
+            {
+                Append(value);
+            }
+
             //Fetch point in list and add new item
             DoublyLinkedListNode<T>? node = Traverse(index - 1);
             node!.Next = DoublyLinkedListNode<T>.Create(value, node.Next, node);
@@ -113,24 +119,39 @@ namespace C_.Datastructures
                 node.Next.Next.Prev = node.Next;
         }
 
-        public bool Delete(int index){
+        public void Delete(int index)
-            DoublyLinkedListNode<T>? node = Traverse(index);
+        {
+            Count--;
+            if (index > Count || index < 0) throw new System.Exception("Error! Index outside of Bounds");
 
-            if (node == default) return false;
+            //Check if we are trying to reference the first item
-
+            if (index == 0 && Head != default)
-            if(node.Prev != default){
+            {
-                //connect item beofre to item after node we are deleting
+                Head = Head!.Next;
-                node.Prev.Next = node.Next;
+                if(Head != default) 
+                    Head.Prev = default;
+                return;
             }
 
+            //Set tail to new item if index is the end
+            if (index == Count && Tail != default)
+            {
+                Tail = Tail!.Prev;
+
+                if(Tail != default) 
+                    Tail.Next = default;
+                return;
+            }
+
+            DoublyLinkedListNode<T>? node = Traverse(index - 1);
+
+            node!.Next = node.Next!.Next;
+
             //Connect item after to the the item before the node we are deleting
             if (node.Next != default)
             {
-                node.Next.Prev = node.Prev;                
+                node.Next.Prev = node;                
             }
-
-            Count--;
-            return true;
         }
 
 

C#/Datastructures/LinkedList.cs

@@ -62,8 +62,8 @@ namespace C_.Datastructures
 
         public void Append(T value){
             //Create new node
-            LinkedListNode<T> newItem = LinkedListNode<T>.Create(value, default);
             Count++;
+            LinkedListNode<T> newItem = LinkedListNode<T>.Create(value, default);
 
             //Set head to new item if list is empty
             if (Head == null) 
@@ -81,14 +81,12 @@ namespace C_.Datastructures
 
             //Append item to end
             end!.Next = newItem;
-
         }
 
         public void Insert(int index, T value)
         {
-            if (index > Count) throw new System.Exception("Error! Index outside of Bounds");
-
             Count++;
+            if (index > Count || index < 0) throw new System.Exception("Error! Index outside of Bounds");
 
             //Set head to new item if list is empty
             if (index == 0 || Head == null)
@@ -105,12 +103,11 @@ namespace C_.Datastructures
 
         public void Delete(int index)
         {
-            if (index > Count) throw new System.Exception("Error! Index outside of Bounds");
-
             Count--;
+            if (index > Count || index < 0) throw new System.Exception("Error! Index outside of Bounds");
 
             //Check if we are trying to reference the first item
-            if (index == 0 && Head != null)
+            if (index == 0 && Head != default)
             {
                 Head = Head!.Next;
                 return;

C#/Program.cs

@@ -5,7 +5,8 @@ using C_.Datastructures.Nodes;
 // See https://aka.ms/new-console-template for more information
 Console.WriteLine("Hello, World!");
 
-//DoublyLinkedList<int> list = new DoublyLinkedList<int>();
+
+//LinkedList<int> list = new LinkedList<int>();
 
 //list.Append(1);
 //list.Append(2);
@@ -13,8 +14,25 @@ Console.WriteLine("Hello, World!");
 //list.Append(4);
 //list.Append(5);
 //list.Append(6);
-//list.Append(7);
+
-//list.Append(8);
+//list.Delete(5);
+//list.Delete(2);
+//list.Delete(0);
+
+
+
+DoublyLinkedList<int> list = new DoublyLinkedList<int>();
+
+list.Append(1);
+list.Append(2);
+list.Append(3);
+list.Append(4);
+list.Append(5);
+list.Append(6);
+
+list.Delete(5);
+list.Delete(3);
+list.Delete(0);
 
 //DoublyLinkedList<int> list2 = new DoublyLinkedList<int>();
 
@@ -27,27 +45,9 @@ Console.WriteLine("Hello, World!");
 //list2.Append(7);
 //list2.Append(8);
 
-//list.Insert(9, 5);
-
-//list.Delete(2);
-
 //var x = list[-6];
 
-//Console.WriteLine(x);
 
-LinkedList<int> list = new LinkedList<int>();
-
-list.Append(1);
-list.Append(2);
-list.Append(3);
-list.Append(4);
-list.Append(5);
-list.Append(6);
-
-list.Insert(0, 200);
-list.Insert(2, 100);
-list.Delete(2);
-list.Delete(0);
 
 Console.ReadLine();