public void TestSetPrevious()
{
Employee emp1 = new Employee(1);
Employee emp2 = new Employee(2);
Node <Employee> node1 = new Node <Employee>(emp1);
Node <Employee> node2 = new Node <Employee>(emp2);
node2.SetPrevious(node1);
Assert.That(node2.GetPrevious(), Is.EqualTo(node1));
}
/// <summary>
/// Adds the data to a new node in the linked list between the nodes specified
/// </summary>
/// <param name="data">Data to add to the list</param>
/// <param name="previous">A pointer to the node that will come before data's node</param>
/// <param name="next">A pointer to the node that will come after the data's node</param>
private void Link(T data, Node <T> previous, Node <T> next)
{
Node <T> newNode = new Node <T>(data, previous, next);
previous.SetNext(newNode);
next.SetPrevious(newNode);
size++;
}
/// <summary>
/// Removes the specified node from the linked list
/// </summary>
/// <param name="node">The node to be removed</param>
/// <returns>Data from the node being removed</returns>
private T Unlink(Node <T> node)
{
Node <T> previous = node.GetPrevious();
Node <T> next = node.GetNext();
previous.SetNext(next);
next.SetPrevious(previous);
size--;
return(node.GetData());
}
/// <summary>
/// Removes the node at the head of the linked list and returns the data it contains
/// </summary>
/// <returns>The data from the unlinked head node</returns>
private T UnlinkHead()
{
Node <T> oldHead = head;
T data;
head = head.GetNext();
size -= 1;
// Determine if head is now null and if it is make the tail null as well
if (head == null)
{
tail = null;
}
head?.SetPrevious(null);
data = oldHead.GetData();
return(data);
}
/// <summary>
/// Adds the node to the head when null if not adds it after the head
/// </summary>
/// <param name="data">The node to be added</param>
private void LinkHead(T data)
{
Node <T> toAdd = new Node <T>(data);
// Determine if the head is null
if (head != null)
{
head.SetPrevious(toAdd);
toAdd.SetNext(head);
}
head = toAdd;
// Determine if the linked list is empty and make the tail also the head
if (size == 0)
{
tail = head;
}
size++;
}
