/// <summary>
/// Passing through the list from end to beginning
/// </summary>
/// <returns>reverse transfer</returns>
//way in other side
public IEnumerator <T> BackEnumerator()
{
DoulbyUnit <T> actual = tail;
while (actual != null)
{
yield return(actual.Data);
actual = actual.Previous;
}
}
/// <summary>
/// Passing through the list from the beginning to the end
/// </summary>
/// <returns>enumeration</returns>
//way in one side
public IEnumerator <T> GetEnumerator()
{
DoulbyUnit <T> actual = head;
while (actual != null)
{
yield return(actual.Data);
actual = actual.Next;
}
}
/// <summary>
/// Determines whether a given value is a list item
/// </summary>
/// <param name="data">Generic type, the search value in the list</param>
/// <returns></returns>
public bool Contains(T data)
{
DoulbyUnit <T> actual = head;
while (actual != null)
{
if (actual.Data.Equals(data))
{
return(true);
}
actual = actual.Next;
}
return(false);
}
/// <summary>
/// Adds an element to the end of the list
/// </summary>
/// <param name="data">Generic type, the added element</param>
public void Add(T data)
{
DoulbyUnit <T> _doulbyUnit = new DoulbyUnit <T>(data);
if (head == null)
{
head = _doulbyUnit;
}
else
{
tail.Next = _doulbyUnit;
tail.Previous = tail;
}
tail = _doulbyUnit;
count++;
}
/// <summary>
/// Adds an element to the head of the list
/// </summary>
/// <param name="data">Generic type, the added element</param>
public void AddFirst(T data)
{
DoulbyUnit <T> _unit = new DoulbyUnit <T>(data);
DoulbyUnit <T> temp = head;
_unit.Next = temp;
head = _unit;
if (count == 0)
{
tail = head;
}
else
{
temp.Previous = _unit;
}
count++;
}
/// <summary>
/// Deletes the specified item from the linked list
/// </summary>
/// <param name="data">Generic type, item to remove</param>
/// <returns></returns>
public bool Remove(T data)
{
DoulbyUnit <T> actual = head;
DoulbyUnit <T> prior = null;
//search element for delete - method Contains
while (actual != null)
{
if (actual.Data.Equals(data))
{
break;
}
actual = actual.Next;
}
if (actual != null)
{
//if element not last
if (actual.Next != null)
{
actual.Next.Previous = actual.Previous;
}
else
{
//if element last
tail = actual.Previous;
}
//if element not first
if (actual.Previous != null)
{
actual.Previous.Next = actual.Next;
}
else
{
//if - first
head = actual.Next;
}
count--;
return(true);
}
return(false);
}
/// <summary>
/// Delete elements from LinkedList
/// </summary>
public void Clear()
{
head = null;
tail = null;
count = 0;
}
