Class 12 Computer Science — Chapter 4: Queue

A student should understand that a queue is a linear data structure that operates on the First In First Out (FIFO) principle, also known as First Come First Served (FCFS). New elements are added to one end, called the REAR (or TAIL), and existing elements are removed from the other end, called the FRONT (or HEAD).

A student should be able to identify and explain real-world and computer science applications of queues, such as managing print jobs, handling requests on a web server, OS process scheduling, and managing customer service calls.

A student must be able to define and differentiate between the two primary queue operations: ENQUEUE, which adds an element to the REAR of the queue, and DEQUEUE, which removes an element from the FRONT. They should also understand the associated error conditions: Overflow (adding to a full queue) and Underflow (removing from an empty queue).

A student should understand the utility of helper functions for queue management, such as IS EMPTY to check if the queue has any elements (to prevent Underflow), PEEK to view the element at the FRONT without removing it, and IS FULL to check if the queue has space for new elements (to prevent Overflow).

A student should learn the practical method of implementing a queue data structure using Python's built-in list type. This includes understanding that the `append()` method can be used for the ENQUEUE operation at the REAR, and the `pop(0)` method can be used for the DEQUEUE operation at the FRONT.

A student should be able to write and use a set of user-defined functions in Python to manage a queue implemented with a list. This includes creating functions for `enqueue`, `dequeue`, `isEmpty`, `peek`, and `size` that encapsulate the queue's logic.

A student should understand the basic concept of a Deque (pronounced 'deck'), which is a double-ended queue. Unlike a standard queue, a Deque allows for the addition and removal of elements from both the FRONT and the REAR.