public bool Remove(T item)
{
if (Count == 0)
{
return(false);
}
DLLNode <T> current = Head;
while (current != null)
{
if (current.Value.Equals(item))
{
// link the next pointer of the previous node to the next node of the current node.
current.Previous.Next = current.Next;
// link the previous pointer of the next node to the previous of the current node.
current.Next.Previous = current.Previous;
Count--;
return(true);
}
current = current.Next;
}
return(false);
}
public void CopyTo(T[] array, int arrayIndex)
{
DLLNode <T> current = Head;
while (current != null)
{
array[arrayIndex++] = current.Value;
current = current.Next;
}
}
public IEnumerator <T> GetEnumerator()
{
DLLNode <T> current = Head;
while (current != null)
{
yield return(current.Value);
current = current.Next;
}
}
public void RemoveLast()
{
if (Count == 0)
{
return;
}
Tail = Tail.Previous;
Count--;
// if there was only one element (meaning Tail.Previous == null) after removing it, clear the Head pointer.
if (Count == 0)
{
Head = null;
}
}
public void RemoveFirst()
{
if (Count == 0)
{
return;
}
Head = Head.Next;
Count--;
// if there was only one element (meaning Head.Next == null) after removing it, clear the Tail pointer.
if (Count == 0)
{
Tail = null;
}
}
public void AddToBack(T item)
{
if (Count == 0)
{
// since it's the fist node.
this.AddToFront(item);
return;
}
var newNode = new DLLNode <T>(item)
{
Previous = Tail
};
Tail.Next = newNode;
Tail = newNode;
Count++;
}
public void AddToFront(T item)
{
var newNode = new DLLNode <T>(item);
if (Count == 0)
{
Head = newNode;
Tail = newNode;
Count++;
return;
}
var currentHead = Head;
Head = newNode;
Head.Next = currentHead;
currentHead.Previous = Head;
Count++;
}
public bool Contains(T item)
{
if (Count == 0)
{
return(false);
}
DLLNode <T> current = Head;
while (current != null)
{
if (current.Value.Equals(item))
{
return(true);
}
current = current.Next;
}
return(false);
}
