public void InsertAtBeginning(TData data)
{
var tempNode = new NodeDoubleLink <TData>(data)
{
NextLink = _startNode
};
_startNode.PreviousLink = tempNode;
_startNode = tempNode;
}
public void InsertAtPosition(TData data)
{
if (_startNode == null)
{
InsertIfListIsNull(data);
return;
}
Console.Write("Enter the position where you want to insert: ");
var position = Convert.ToInt32(Console.ReadLine());
if (position == 0)
{
return;
}
if (position == 1)
{
InsertAtBeginning(data);
return;
}
int index;
var currentNode = _startNode;
for (index = 1; index < position - 1 && currentNode != null; index++)
{
currentNode = currentNode.NextLink;
}
if (currentNode == null)
{
Console.WriteLine($"You can insert only upto {index}th position.");
}
else
{
var newNode = new NodeDoubleLink <TData>
{
Data = data,
NextLink = currentNode.NextLink,
PreviousLink = currentNode
};
if (currentNode.NextLink != null)
{
currentNode.NextLink.PreviousLink = newNode;
}
currentNode.NextLink = newNode;
}
}
public void DeleteLast()
{
if (_startNode?.NextLink == null)
{
_startNode = null;
return;
}
var currentNode = _startNode;
while (currentNode.NextLink.NextLink != null)
{
currentNode = currentNode.NextLink;
}
currentNode.NextLink = null;
}
public void DeleteFirst()
{
if (_startNode == null)
{
return;
}
if (_startNode.NextLink != null)
{
_startNode = _startNode.NextLink;
_startNode.PreviousLink = null;
return;
}
_startNode = null;
}
public void InsertAfter(TData data)
{
if (_startNode == null)
{
InsertIfListIsNull(data);
return;
}
Console.Write("Enter the element after which you want to insert");
var nodeValue = (TData)Convert.ChangeType(Console.ReadLine(), typeof(TData));
var currentNode = _startNode;
while (currentNode != null)
{
if (currentNode.Data.CompareTo(nodeValue) == 0)
{
break;
}
currentNode = currentNode.NextLink;
}
if (currentNode == null)
{
Console.WriteLine($"Node with value {nodeValue} is not present in the list.");
}
else
{
var tempNode = new NodeDoubleLink <TData>(data)
{
NextLink = currentNode.NextLink, PreviousLink = currentNode
};
if (currentNode.NextLink != null)
{
currentNode.NextLink.PreviousLink = tempNode;
}
currentNode.NextLink = tempNode;
}
}
public void InsertAtEnd(TData data)
{
if (_startNode == null)
{
InsertIfListIsNull(data);
return;
}
var currentNode = _startNode;
while (currentNode.NextLink != null)
{
currentNode = currentNode.NextLink;
}
var tempNode = new NodeDoubleLink <TData>(data);
currentNode.NextLink = tempNode;
tempNode.PreviousLink = currentNode;
}
public void ReverseList()
{
if (_startNode?.NextLink == null)
{
return;
}
var currentNode = _startNode;
var nextNode = currentNode.NextLink;
currentNode.NextLink = null;
currentNode.PreviousLink = nextNode;
while (nextNode != null)
{
nextNode.PreviousLink = nextNode.NextLink;
nextNode.NextLink = currentNode;
currentNode = nextNode;
nextNode = nextNode.PreviousLink;
}
_startNode = currentNode;
}
public DoubleLinkedList()
{
_startNode = null;
}
public void InsertIfListIsNull(TData data)
{
var tempNode = new NodeDoubleLink <TData>(data);
_startNode = tempNode;
}
public NodeDoubleLink(TData data)
{
Data = data;
PreviousLink = null;
NextLink = null;
}
