
1038 CHAPTER 14 An Introduction to Data Structures
Figure 14.9
A Queue of People Wait-
ing at the ATM
ATM
frontback
Like our previous linked list implementation, it is very important to test if
the stack is empty before trying to delete a node; failure to do so will gener-
ate a NullPointerException at run time.
A similar program to Example 14.9 can be coded to test all possible scenar-
ios when using the methods of the PlayerStackLinkedList class. This is pro-
posed in the short program section of the exercises.
14.4 Implementing a Queue Using a Linked List
Imagine a line of people at an automated teller machine, or ATM, waiting
to withdraw cash. The person ...