public void RemoveBack()
{
if (_count > 1)
{
_tail = _tail.Prev;
_tail.Next = null;
_count--;
}
else
{
_head = _tail = null;
_count = 0;
}
}
public void RemoveFront()
{
if (_count > 1)
{
_head = _head.Next;
_head.Prev = null;
_count--;
}
else
{
_head = _tail = null;
_count = 0;
}
}
public void Add(T item)
{
if (_count == 0)
{
_head = _tail = new DLNode <T>(item);
_count++;
}
else
{
DLNode <T> newnode = new DLNode <T>(item, _tail);
_tail.Next = newnode;
_tail = newnode;
_count++;
}
}
public void AddFront(T item)
{
if (_count == 0)
{
_head = _tail = new DLNode <T>(item);
_count++;
}
else
{
var newnode = new DLNode <T>(item, null, _head);
_head.Prev = newnode;
_head = newnode;
_count++;
}
}
public void Insert(int index, T item)
{
if (index == 0)
{
AddFront(item);
}
else if (index > 0 && index < _count)
{
var current = GetNode(index);
DLNode <T> new_node = new DLNode <T>(item, current.Prev, current);
current.Prev.Next = new_node;
current.Prev = new_node;
_count++;
}
else if (index == _count)
{
Add(item);
}
}
public void Clear()
{
_head.Prev = _head.Next = _tail.Prev = _tail.Next = _tail = _head = null;
_count = 0;
}
public DLNode(T value, DLNode <T> prev = null, DLNode <T> next = null)
{
_value = value;
_ptr_prev = prev;
_ptr_next = next;
}
