} // end method InsertAtBack
// remove first node from List
public object RemoveFromFront()
{
if (IsEmpty())
{
throw new EmptyListException(name);
}
object removeItem = firstNode.Data; // retrieve data
// reset firstNode and lastNode references
if (firstNode == lastNode)
{
firstNode = lastNode = null;
}
else
{
firstNode = firstNode.Next;
}
return(removeItem); // return removed data
} // end method RemoveFromFront
} // end method IsEmpty
// output List contents
public void Display()
{
if (IsEmpty())
{
Console.WriteLine("Empty " + name);
} // end if
else
{
Console.Write("The " + name + " is: ");
ListNode current = firstNode;
// output current node data while not at end of list
while (current != null)
{
Console.Write(current.Data + " ");
current = current.Next;
} // end while
Console.WriteLine("\n");
} // end else
} // end method Display
private string name; // string like "list" to display
#endregion Fields
#region Constructors
// construct empty List with specified name
public List( string listName )
{
name = listName;
firstNode = lastNode = null;
}
// constructor to create ListNode that refers to dataValue
// and refers to next ListNode in List
public ListNode( object dataValue, ListNode nextNode )
{
Data = dataValue;
Next = nextNode;
}
// remove first node from List
public object RemoveFromFront()
{
if ( IsEmpty() )
throw new EmptyListException( name );
object removeItem = firstNode.Data; // retrieve data
// reset firstNode and lastNode references
if ( firstNode == lastNode )
firstNode = lastNode = null;
else
firstNode = firstNode.Next;
return removeItem; // return removed data
}
// remove last node from List
public object RemoveFromBack()
{
if ( IsEmpty() )
throw new EmptyListException( name );
object removeItem = lastNode.Data; // retrieve data
// reset firstNode and lastNode references
if ( firstNode == lastNode )
firstNode = lastNode = null;
else
{
ListNode current = firstNode;
// loop while current node is not lastNode
while ( current.Next != lastNode )
current = current.Next; // move to next node
// current is new lastNode
lastNode = current;
current.Next = null;
} // end else
return removeItem; // return removed data
}
// Insert object at front of List. If List is empty,
// firstNode and lastNode will refer to same object.
// Otherwise, firstNode refers to new node.
public void InsertAtFront( object insertItem )
{
if ( IsEmpty() )
firstNode = lastNode = new ListNode( insertItem );
else
firstNode = new ListNode( insertItem, firstNode );
}
// Insert object at end of List. If List is empty,
// firstNode and lastNode will refer to same object.
// Otherwise, lastNode's Next property refers to new node.
public void InsertAtBack( object insertItem )
{
if ( IsEmpty() )
firstNode = lastNode = new ListNode( insertItem );
else
lastNode = lastNode.Next = new ListNode( insertItem );
}
private string name; // string like "list" to display
// construct empty List with specified name
public List(string listName)
{
name = listName;
firstNode = lastNode = null;
} // end constructor
} // end default constructor
// constructor to create ListNode that refers to dataValue
// and refers to next ListNode in List
public ListNode(object dataValue, ListNode nextNode)
{
Data = dataValue;
Next = nextNode;
} // end constructor
// constructor to create ListNode that refers to dataValue
// and refers to next ListNode in List
public ListNode(double dataValue, ListNode nextNode)
{
Data = dataValue;
Next = nextNode;
}
