public int RemoveLast()
{
if (this.Count == 0)
{
throw new InvalidOperationException("The List is empty");
}
int removedElement = this.tail.Value;
if (this.Count == 1)
{
this.head = this.tail = null;
}
else
{
this.tail = this.tail.PreviousNode;
this.tail.NextNode = null;
}
this.Count--;
return(removedElement);
}
public int RemoveLast()
{
if (this.Count == 0)
{
throw new InvalidOperationException("The list is empty.");
}
var lastElement = this.tail.Value;
this.tail = this.tail.PreviousNode;
if (this.tail != null)
{
this.tail.NextNode = null;
}
else
{
this.head = null;
}
this.Count--;
return(lastElement);
}
/// <summary>
/// Adds an element at the end of the collection.
/// </summary>
/// <param name="element">The value to enter.</param>
public void AddLast(T element)
{
if (this.Count == 0)
{
this.AddFirst(element);
}
else if (this.Count == 1)
{
var oldTail = this.Tail;
this.Head = oldTail;
this.Tail = new ListNode <T>(element, oldTail, null);
this.Head.Next = this.Tail;
this.Count++;
}
else
{
var innerElement = this.Tail;
this.Tail = new ListNode <T>(element, innerElement, null);
innerElement.Next = this.Tail;
this.Count++;
}
}
public T RemoveFirst()
{
T removedEl = this.head.Value;
if (this.Count == 0)
{
throw new InvalidOperationException("List is empty.");
}
else if (this.Count == 1)
{
this.head = null;
this.tail = null;
}
else
{
ListNode <T> newHead = this.head.NextNode;
newHead.PreviousNode = null;
this.head = newHead;
}
this.Count--;
return(removedEl);
}
/// <summary>
/// Adds an element at the beginning of the collection.
/// </summary>
/// <param name="element">The value to enter.</param>
public void AddFirst(T element)
{
if (this.Count == 0)
{
this.Head = new ListNode <T>(element, null, null);
this.Tail = this.Head;
}
else if (this.Count == 1)
{
var oldHead = this.Head;
this.Tail = oldHead;
this.Head = new ListNode <T>(element, null, this.Tail);
this.Tail.Previous = this.Head;
}
else
{
var innerElement = this.Head;
this.Head = new ListNode <T>(element, null, innerElement);
innerElement.Previous = this.Head;
}
this.Count++;
}
