Download CHAPTER 18 Linked Lists, Stacks, Queues, and Priority

tail
tail = tail.next
head
"Chicago"
"Denver"
"Dallas"
n ext
next
next: None
(b)
Figure 18.5
Append the third node to the list.
To append the new node to the list, link the last node in the list with the new node, as shown in Figure
18.5a. The new node is now the tail node. So you should move tail to point to this new node, as shown in
Figure 18.5b.
Each node contains the element and a data field named next that points
to the next element. If the node is the last in the list, its pointer
data field next contains the value None. You can use this property to
detect the last node. For example, you may write the following loop to
traverse all the nodes in the list.
current = head
while current != None:
print(current.element)
current = current.next
The variable current points initially to the first node in the list
(line 1). In the loop, the element of the current node is retrieved
(line 3), and then current points to the next node (line 4). The loop
continues until the current node is None.
18.2.1 The LinkedList Class
The LinkedList class can be defined in a UML diagram in Figure 18.6.
The solid diamond indicates that LinkedList contains nodes. For
references on the notations in the diagram, see Section 8.8.
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