What is Circular Queue | Circular Queue meaning

A circular queue is an extended version of regular queue in which the last element of the queue is connected to the first element of the queue forming a cycle.

Properties of Circular Queue:

Along with the properties of a regular queue the circular queue has som other unique properties as mentioned below:

• Front and rear pointers: Two pointers, one at the front and one at the back, are present in a circular queue. The front pointer points to the first member in the queue, while the rear pointer points to the last member in the queue.
• Fixed size: The size of a circular queue is established at initialization. If the queue is already full, additional components cannot be added without first being dequeued.
• Circular data structure: A circular queue is a data structure with a circle-like connection between the last and first positions. This indicates that the rear pointer rolls around to the beginning of the array when it reaches the end.
• Overwriting: When an element is added to a circular queue that is already full, it overwrites the oldest element there, which is located at the front of the queue.
• Effective memory use: A circular queue effectively uses memory by recycling the empty spaces left behind when elements are dequeued.

Applications of Circular Queue:

Following are a few applications of Circular Queue:

• CPU scheduling: The circular queue can be used in operating systems to manage processes that are waiting to be executed. Each process is added to the circular queue and scheduled to run based on its priority level.
• Music players: A circular queue can be used in music players to manage playlists.. When a song finishes playing, the circular queue moves to the next song in the list and starts playing it.
• Buffering data: In networking and multimedia applications, circular queues can be used to buffer data streams. This helps to smooth out fluctuations in network traffic and ensures that data is delivered at a consistent rate.
• Simulation systems: Circular queues can be used in simulation systems to model real-world processes. For example, in a traffic simulation, a circular queue can be used to model the movement of cars through an intersection.
• Audio and video processing: In audio and video processing systems, circular queues can be used to store and process samples of sound or video data. This helps to ensure that the data is processed in the correct order and at a consistent rate.

To learn more about the applications of a circular queue, refer to this article.

Advantages of Circular Queue:

• Efficient use of memory: Circular queues that are constructed using an array data structure, making effective use of the available memory. 
• Simple to create: With a fixed-size array to store the queue components and a few pointers to track the front and back of the queue, circular queues are comparatively simple to implement.
• Data overwriting: The oldest element in a circular queue is rewritten when the queue is full and a new element is enqueued. In applications where earlier data is no longer usable, this means that the queue can be utilized to hold only the most current data.
• Cyclic Nature: Circular queues' cyclical structure makes them ideal for applications with cyclic patterns or in which data is accessed in circles. Applications like network traffic management, simulations, and traffic management may fall under this category.

To learn more about the advantages of a circular queue, refer to this article.

Disadvantages of Circular Queue:

• Limited capacity: A circular queue has a fixed size, which means that it can only hold a certain number of elements. If the size of the queue is exceeded, new elements cannot be added.
• Complex to debug: Debugging a circular queue can be more complex than debugging a regular queue because of its circular nature. This can make it more difficult to identify and fix issues that arise.
• Potential for data loss: If the queue becomes full and new items are added, the oldest items in the queue will be overwritten. This can lead to data loss and may not be desirable in certain applications.

To learn more about the disadvantages of a circular queue, refer to this article.

What else can you read?

• Introduction and Array Implementation of Circular Queue
• Advantage of Circular Queue over linear queue
• Circular Linked List Implementation of Circular Queue