public IEnumerable <ListNode> BackEnumerator()
{
DoublyNode <ListNode> current = tail;
while (current != null)
{
yield return(current.Data);
current = current.Previous;
}
}
IEnumerator <ListNode> IEnumerable <ListNode> .GetEnumerator()
{
DoublyNode <ListNode> current = head;
while (current != null)
{
yield return(current.Data);
current = current.Next;
}
}
public bool Contains(ListNode data)
{
DoublyNode <ListNode> current = head;
while (current != null)
{
if (current.Data.Equals(data))
{
return(true);
}
current = current.Next;
}
return(false);
}
public void Add(ListNode data)
{
DoublyNode <ListNode> node = new DoublyNode <ListNode>(data);
if (head == null)
{
head = node;
}
else
{
tail.Next = node;
node.Previous = tail;
}
tail = node;
count++;
}
public void AddFirst(ListNode data)
{
DoublyNode <ListNode> node = new DoublyNode <ListNode>(data);
DoublyNode <ListNode> temp = head;
node.Next = temp;
head = node;
if (count == 0)
{
tail = head;
}
else
{
temp.Previous = node;
}
count++;
}
public bool Remove(ListNode data)
{
DoublyNode <ListNode> current = head;
while (current != null)
{
if (current.Data.Equals(data))
{
break;
}
current = current.Next;
}
if (current != null)
{
if (current.Next != null)
{
current.Next.Previous = current.Previous;
}
else
{
tail = current.Previous;
}
if (current.Previous != null)
{
current.Previous.Next = current.Next;
}
else
{
head = current.Next;
}
count--;
return(true);
}
return(false);
}
public void Clear()
{
head = null;
tail = null;
count = 0;
}
