public IEnumerator <T> GetEnumerator()
{
DoublyNode <T> current = head;
while (current != null)
{
yield return(current.Data);
current = current.Next;
}
}
public int Count; // количество элементов в списке
// добавление элемента
public void Add(T data)
{
var node = new DoublyNode <T>(data);
if (head == null)
{
head = node;
}
else
{
tail.Next = node;
node.Previous = tail;
}
tail = node;
Count++;
}
public void RemoveAt(int index)
{
var current = head;
var k = 0;
if (index > 0 && index < Count)
{
while (k < index)
{
current = current.Next;
k++;
}
if (current != null)
{
// если узел не последний
if (current.Next != null)
{
current.Next.Previous = current.Previous;
}
else
{
// если последний, переустанавливаем tail
tail = current.Previous;
}
// если узел не первый
if (current.Previous != null)
{
current.Previous.Next = current.Next;
}
else
{
// если первый, переустанавливаем head
head = current.Next;
}
Count--;
}
}
else
{
throw new ArgumentOutOfRangeException("Index was out of range. " +
"Must be non-negative and less than the size of the collection. " +
"(Parameter 'index')");
}
}
public void AddAt(T data, int index)
{
var node = new DoublyNode <T>(data);
var current = head;
if (index == 0)
{
node.Next = current;
head = node;
if (Count == 0)
{
tail = head;
}
else
{
current.Previous = node;
}
}
else
{
if (index > 0 && index < Count)
{
var k = 1;
while (k < index)
{
current = current.Next;
k++;
}
node.Next = current.Next;
current.Next = node;
node.Previous = current.Next;
}
else
{
throw new ArgumentOutOfRangeException("Index was out of range. " +
"Must be non-negative and less than the size of the collection. " +
"(Parameter 'index')");
}
}
Count++;
}