Queues and Priority Queues

Objectives

• To gain familiarity with object oriented programming (OOP) in php
• To continue to gain familiarity with arrays
• To continue to gain familiarity with php

Part I: Queue Implementation

Implement a queue in a file named queue.php such that when this file (renamed lab.php) is run, it produces this output exactly. Remember to view the source in order to see the exact details.

Part II: Priority Queue Implementation

Implement a priority queue in a file named priorityQueue.php such that when this file (renamed lab.php and suitably modified to use a priority queue instead of a queue) is run, it produces this output exactly.

Helpful Hints

• Use an array as the underlying data structure. Arrays in php are ordered maps that can consequently be used to implement lists, hash tables, stacks, queues and many other abstract data types (ADTs).
• Do Part I first as you should be able to reuse much of this solution for Part II.

Requirements

• This file (renamed item.php) is used without modification in your solution.
• The queue.php contains a protected method named isEmpty that is used by the dequeue method.
• The queue.php file uses access modifiers correctly.
• The queue.php file generates the correct answer.
• The priorityQueue.php file contains as few functions as possible.
• The priorityQueue.php file generates the correct answer.