A circular queue is a special type of queue data structure that uses a fixed-size array with wrap-around behavior. Unlike a regular queue, when we reach the end of the array, we wrap back to the beginning, creating a circular effect. This design uses two pointers called front and rear to track the queue's boundaries, and employs the modulo operator to handle the wrap-around efficiently.
The enqueue operation adds an element to the rear of the circular queue. First, we check if the queue is full using the condition: rear plus one modulo capacity equals front. If not full, we increment the rear pointer using modulo arithmetic to handle wrap-around, then insert the new element at the rear position. Let's see how we add element C to our queue.
The dequeue operation removes an element from the front of the circular queue. First, we check if the queue is empty by comparing front and rear pointers or using a size counter. If not empty, we retrieve the element at the front position, then increment the front pointer using modulo arithmetic for wrap-around. Let's see how we remove element A from our queue.
The wrap-around behavior is the key feature of circular queues. When the rear pointer reaches the end of the array at index 5, the next position wraps around to index 0 using modulo arithmetic. Similarly, when the front pointer reaches the end, it wraps back to the beginning. This creates a circular effect, allowing efficient use of the entire array space.
To summarize what we've learned about circular queues: They use a fixed-size array with wrap-around behavior managed by front and rear pointers. The modulo operator enables efficient circular movement, preventing memory waste found in traditional linear queues. This makes circular queues ideal for buffering systems and resource management applications where efficient memory usage is crucial.