IEnumerator <T> IEnumerable <T> .GetEnumerator()
{
DoublyNode <T> current = head;
do
{
if (current != null)
{
yield return(current.Data);
current = current.Next;
}
} while (current != head);
}
public void Add(T data)
{
DoublyNode <T> node = new DoublyNode <T>(data);
if (head == null)
{
head = node;
head.Next = node;
head.Previous = node;
}
else
{
node.Previous = head.Previous;
node.Next = head;
head.Previous.Next = node;
head.Previous = node;
}
count++;
}
public bool Contains(T data)
{
DoublyNode <T> current = head;
if (current == null)
{
return(false);
}
do
{
if (current.Data.Equals(data))
{
return(true);
}
current = current.Next;
} while (current != head);
return(false);
}
public bool Remove(T data)
{
DoublyNode <T> current = head;
DoublyNode <T> removedItem = null;
if (count == 0)
{
return(false);
}
do
{
if (current.Data.Equals(data))
{
removedItem = current;
break;
}
current = current.Next;
}while (current != head);
if (removedItem != null)
{
if (count == 1)
{
head = null;
}
else
{
if (removedItem == head)
{
head = head.Next;
}
removedItem.Previous.Next = removedItem.Next;
removedItem.Next.Previous = removedItem.Previous;
}
count--;
return(true);
}
return(false);
}
public void Clear()
{
head = null;
count = 0;
}