/// <summary>
/// Returns the node containing the data specified
/// </summary>
/// <param name="data">The data to look for in the linked list</param>
/// <returns>The node that contains the data</returns>
private Node <T> Find(T data)
{
Node <T> current = head;
T currentData;
bool firstIteration = true;
// While data is not equal to current data loop
do
{
// Determine if first iteration, if it is make first iteration false and after update current
if (firstIteration)
{
firstIteration = false;
}
else
{
current = current.GetNext();
}
// Determine if current is null
if (current == null)
{
return(null);
}
else
{
currentData = current.GetData();
}
} while (currentData.CompareTo(data) < 0 || currentData.CompareTo(data) > 0);
return(current);
}
public void TestDataArgContructor()
{
Employee emp1 = new Employee(1);
Node <Employee> node1 = new Node <Employee>(emp1);
Assert.That(node1, Is.Not.Null);
Assert.That(node1.GetData(), Is.EqualTo(emp1));
Assert.That(node1.GetNext(), Is.Null);
Assert.That(node1.GetPrevious(), Is.Null);
}
public void TestGetNext()
{
Employee emp1 = new Employee(1);
Employee emp2 = new Employee(2);
Employee emp3 = new Employee(3);
Node <Employee> node1 = new Node <Employee>(emp1);
Node <Employee> node2 = new Node <Employee>(emp2);
Node <Employee> testNode = new Node <Employee>(emp3, node1, node2);
Assert.That(testNode.GetNext(), Is.EqualTo(node2));
}
/// <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>
/// Returns the node at the position number specified
/// </summary>
/// <param name="position">Numeric position of node to look for</param>
/// <returns>Returns the node</returns>
private Node <T> Find(int position)
{
Node <T> current = head;
int i = 1;
while (i < position)
{
current = current.GetNext();
i++;
}
return(current);
}
public void TestAllArgContructor()
{
Employee emp1 = new Employee(1);
Employee emp2 = new Employee(2);
Employee emp3 = new Employee(3);
Node <Employee> node1 = new Node <Employee>(emp1);
Node <Employee> node2 = new Node <Employee>(emp2);
Node <Employee> testNode = new Node <Employee>(emp3, node1, node2);
Assert.That(testNode, Is.Not.Null);
Assert.That(testNode.GetData(), Is.EqualTo(emp3));
Assert.That(testNode.GetNext(), Is.EqualTo(node2));
Assert.That(testNode.GetPrevious(), Is.EqualTo(node1));
}
/// <summary>
/// The new node containing data is to be added to the linked list after the node at the specified number.
/// </summary>
/// <param name="data">Data to add</param>
/// <param name="position">The number of the node to add after</param>
/// <returns>True when complete</returns>
public bool AddAfter(T data, int position)
{
ValidatePositon(position);
// Determine if possition is equal to size
if (position == size)
{
LinkTail(data);
}
else
{
Node <T> previous = Find(position);
Node <T> next = previous.GetNext();
Link(data, previous, next);
}
return(true);
}
/// <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>
/// A node containing the supplied data value is to be added after the node containing oldData
/// </summary>
/// <param name="data">The data to be added to the list</param>
/// <param name="oldData">Value used to to find the node containing the oldData</param>
/// <returns>True when complete</returns>
public bool AddAfter(T data, T oldData)
{
Node <T> node = Find(oldData);
// Determine if node is null and throw exception if it is
if (node == null)
{
throw new IndexOutOfRangeException("No such element");
}
else
{
// Dtermine if the node is the tail
if (node == tail)
{
LinkTail(data);
}
else
{
Link(data, node, node.GetNext());
}
}
return(true);
}
