public Node Add(string word)
{
Node newNode =new Node();
newNode.Word = word;
newNode.next = null;
if (First == null)
{
newNode.previous = null;
First = newNode;
Last = First;
//Current = First;
//Current.next = null;
}
else
{
//Current = newNode;
Last.next = newNode;
newNode.previous = Last;
//Current.next = null;
Last = newNode;
}
return Last;
}
//public string PreviousValue()
//{
// if (Current.previous != null)
// {
// Current = Current.previous;
// }
// return Current.Word;
//}
//public string NextValue()
//{
// if(Current.next != null)
// {
// Current = Current.next;
// }
// return Current.Word;
//}
public Node DeleteNode(Node currentPointer)
{
String CurrentLocation = WhereIsCurrent(currentPointer);
//MessageBox.Show(CurrentLocation);
//return currentPointer;
switch (CurrentLocation)
{
case "AtFirstNode":
MessageBox.Show("Deleting First node");
//First = currentPointer.next;
First = First.next;
First.previous = null;
currentPointer.next = null;
currentPointer = First;
//currentPointer = currentPointer.next;
//First = Current.next;
//First.previous = null;
//Current.previous = null;
//Current.next = null;
//Current = First;
break;
case "AtLastNode":
MessageBox.Show("Deleting last node");
Last = Last.previous;
Last.next = null;
currentPointer.previous = null;
currentPointer = Last;
//Last = Current.previous;
//Last.next = null;
//Current.previous = null;
//Current.next = null;
//Current = Last;
break;
case "InTheMiddle":
MessageBox.Show("Deleting Middle node");
currentPointer.previous.next = currentPointer.next;
currentPointer.next.previous = currentPointer.previous;
Current = currentPointer;
currentPointer = Current.next;
Current.next = Current.previous = null;
break;
}
//if( (Current.next != null) && (Current.next != null) )
// {
// Current.previous.next = Current.next;
// Current.next.previous = Current.previous.previous;
// Current = Current.next;
// }
//else if ( Current.next == null )
//{
// Last = Current.previous;
// Last.next = null;
// Current.previous = null;
// Current.next = null;
// Current = Last;
// }
// else if( (Current.previous == null) )
//{
// First = Current.next;
// First.previous = null;
// Current.previous = null;
// Current.next = null;
// Current = First;
// }
return currentPointer;
}
private string WhereIsCurrent(Node currentPointer)
{
if (currentPointer == First && currentPointer == Last)
{
return "OnlyOneNode";
}
if(currentPointer.previous == null)
{
return "AtFirstNode";
}
if (currentPointer.next == null)
{
return "AtLastNode";
}
return "InTheMiddle";
}