What is a queue in C and how is it implemented?

Table of Contents

• Introduction
• Queue Operations
  • 1. Enqueue
  • 2. Dequeue
  • 3. Front
  • 4. Rear
  • 5. IsEmpty
• Implementation of a Queue in C
  • Using Arrays
  • Using Linked Lists
• Conclusion

Introduction

A queue is a data structure that operates on a First In, First Out (FIFO) basis, meaning that the first element added is the first one to be removed. It is commonly used in various applications such as task scheduling, buffering, and managing requests. In C, queues can be implemented using arrays or linked lists. This guide explains the concept of queues and provides implementation examples in C.

Queue Operations

A queue supports several essential operations:

1. Enqueue

Adds an element to the rear of the queue.

2. Dequeue

Removes an element from the front of the queue.

3. Front

Returns the element at the front of the queue without removing it.

4. Rear

Returns the element at the rear of the queue without removing it.

5. IsEmpty

Checks whether the queue is empty.

Implementation of a Queue in C

Using Arrays

An array-based queue uses a fixed-size array along with two indices to keep track of the front and rear of the queue.

Implementation Example:

Using Linked Lists

A linked list-based queue uses nodes where each node contains data and a pointer to the next node. The front pointer points to the head of the list, and the rear pointer points to the tail.

Implementation Example:

Conclusion

Queues in C can be implemented using arrays or linked lists, each with its pros and cons. Array-based queues are straightforward and efficient for a fixed size, while linked-list-based queues provide flexibility with dynamic sizing but involve extra memory overhead. Understanding these implementations is crucial for effectively managing data and solving problems in C programming.