public SentinelList()
{
_Head = new DListNode <T>(default(T), null, null);
_Head.Next = _Head;
_Head.Prev = _Head;
_Size = 0;
}
public void InsertEnd(T item)
{
DListNode <T> node = new DListNode <T>(item, this._Head, this._Head.Prev);
this._Head.Prev.Next = node;
this._Head.Prev = node;
_Size++;
}
public void InsertFront(T item)
{
DListNode <T> node = new DListNode <T>(item, this._Head.Next, this._Head);
this._Head.Next.Prev = node;
this._Head.Next = node;
_Size++;
}
public void InsertAfterThis(T item)
{
DListNode <T> node = new DListNode <T>(item, this.Next, this);
if (this.Next != null)
{
this.Next.Prev = node;
}
this.Next = node;
}
public void InsertFront(T item)
{
DListNode <T> node = new DListNode <T>(item, this._Head, null);
if (this._Head != null)
{
this._Head.Prev = node;
}
this._Head = node;
if (this._Tail == null)
{
this._Tail = this._Head;
}
_Size++;
}
public void InsertEnd(T item)
{
DListNode <T> node = new DListNode <T>(item, null, this._Tail);
if (this._Tail != null)
{
_Tail.Next = node;
}
this._Tail = node;
if (this._Head == null)
{
this._Head = this._Tail;
}
_Size++;
}
public void RemoveTail() // 2 or more
{
if (this._Tail == null)
{
throw new Exception();
}
if (this._Tail.Prev == null)
{
this._Tail = null;
this._Head = null;
}
else
{
this._Tail.Prev.Next = null;
this._Tail = this._Tail.Prev;
}
_Size--;
}
public DListNode(T item, DListNode <T> next, DListNode <T> prev)
{
this.Item = item;
this.Next = next;
this.Prev = prev;
}
public DList()
{
_Head = null;
_Tail = null;
_Size = 0;
}
