public T RemoveLast()
{
if (this.Count == 0)
{
throw new InvalidOperationException("List empty");
}
var currentTail = this.Tail.Value;
//get current tail pravious element and make it the new tail
this.Tail = this.Tail.Previous;
if (this.Tail != null)
{
//if tail exist make next element null since it is las element in the collection
this.Tail.Next = null;
}
else
{
//if not this mean that collection is empty
//so head must be asign null since the head is old Tail element
this.Head = null;
}
this.Count--;
return(currentTail);
}
public void AddLast(T element)
{
if (this.Count == 0)
{
this.Head = this.Tail = new DoublyListNode <T>(element);
}
else
{
var newHead = new DoublyListNode <T>(element);
newHead.Previous = this.Tail;
this.Tail.Next = newHead;
this.Tail = newHead;
}
this.Count++;
}
public T RemoveFirst()
{
if (this.Count == 0)
{
throw new InvalidOperationException("List empty");
}
var currentHead = this.Head.Value;
this.Head = this.Head.Next;
if (this.Head != null)
{
this.Head.Previous = null;
}
else
{
this.Tail = null;
}
this.Count--;
return(currentHead);
}