Introduction to Queue
Introduction to Queue
- Queue is a list of elements in which an element is inserted at one end and deleted from the other end of the queue.
- Elements are inserted at the rear end and deleted from the front end.
Various operations implemented on a queue are:
- Insert
- Delete
Insert:
- It refers to the addition of an item in the queue.
- Suppose you want to add an item F in the following queue.
- Since the items are inserted at the rear end, therefore, F is inserted after D.
- Now F becomes the rear end.
Delete:
- It refers to the deletion of an item from the queue.
- Since the items are deleted from the front end, therefore, item B is removed from the queue.
- Now A becomes the front end of the queue.
Implementing a Queue
- You can implement a queue by using an array or a linked list.
- A queue implemented in the form of a linked list is known as a linked queue
- To keep track of the rear and front positions, you need to declare two variables/pointers, REAR and FRONT.
- If the queue is empty, REAR and FRONT point to NULL.
