/// <summary>
/// Inserts given element at given index
/// </summary>
/// <param name="element">Element</param>
/// <param name="index">insertion index</param>
/// <exception cref="System.IndexOutOfRangeException">Thrown when the index is either lesser
/// than 0 or greater than the length of the collection</exception>
public override void InsertAt(T element, int index)
{
if (index < 0 || index > Length)
{
throw new IndexOutOfRangeException();
}
if (index == 0)
{
if (_head == null)
{
Add(element);
return;
}
var prevHead = _head;
_head = new DoubleLinkedElement <T>(element, null, prevHead);
prevHead.Prev = _head;
++Length;
return;
}
var current = _head;
for (var i = 0; i < index - 1; i++)
{
current = current.Next;
}
var previousNext = current.Next;
current.Next = new DoubleLinkedElement <T>(element, current, previousNext);
previousNext.Prev = current.Next;
++Length;
}
/// <summary>
/// Removes element of the collection
/// </summary>
/// <param name="index">Deletion index</param>
/// <exception cref="System.IndexOutOfRangeException">Thrown when the index is either lesser
/// than 0 or greater or equal to the length of the collection</exception>
public void RemoveAt(int removeIndex)
{
if (_head == null)
{
return;
}
if (removeIndex < 0 || removeIndex >= Length)
{
throw new IndexOutOfRangeException();
}
if (removeIndex == 0)
{
_head = _head.Next;
--Length;
return;
}
var current = _head;
for (var i = 0; i < removeIndex; i++)
{
current = current.Next;
}
current.Prev.Next = current.Next;
current = null;
--Length;
}
/// <summary>
/// Returns the last element of the collection
/// </summary>
/// <returns>
/// The last element of the collection
/// </returns>
/// <exception cref="System.IndexOutOfRangeException">Thrown when the collection is empty</exception>
public T Pop()
{
if (_last == null)
{
throw new IndexOutOfRangeException();
}
--Length;
var currentLast = _last;
_last = currentLast.Prev;
return(currentLast.Value);
}
/// <summary>
/// Adds element to the end of the collection
/// </summary>
/// <param name="element">Element that will be added</param>
public void Add(T element)
{
++Length;
if (_head == null)
{
_head = new DoubleLinkedElement <T>(element);
return;
}
var current = _head;
while (current.Next != null)
{
current = current.Next;
}
current.Next = new DoubleLinkedElement <T>(element, current);
}
/// <summary>
/// Adds element to collection
/// </summary>
/// <param name="element">Element</param>
public void Push(T element)
{
++Length;
if (_last == null)
{
_last = new DoubleLinkedElement <T>(element);
if (_first == null)
{
_first = _last;
}
else
{
_first.Next = _last;
_last.Prev = _first;
}
return;
}
_last.Next = new DoubleLinkedElement <T>(element, _last);
_last = _last.Next;
}
public DoubleLinkedElement(T value, DoubleLinkedElement <T> prev = null, DoubleLinkedElement <T> next = null)
{
Value = value;
Prev = prev;
Next = next;
}
public DoubleLinkedList()
{
_head = null;
}
