Circular Queue Data Structure

A Circular Queue is an extended version of a linear queue that resolves space wastage by conceptually joining the end of the array back to the beginning to form a loop.

Why Do We Need a Circular Queue?

In a standard linear queue, once rear reaches the end index (MAX - 1), you cannot insert more elements even if there is vacant space at the beginning due to preceding dequeues.

A circular queue overcomes this limitation using modulo arithmetic to wrap pointers back to index 0:

Pointer Increment: index = (index + 1) % MAX

Key Operations & Modulo Conditions

Queue Full Check:
```
isFull = ((rear + 1) % MAX == front)
```
If the next cell after rear wraps around directly to front, the queue is full.
Queue Empty Check:
```
isEmpty = (front == -1)
```
Circular Enqueue:
- If empty: set front = 0, rear = 0.
- Else: increment rear circularly: rear = (rear + 1) % MAX.
- Store: arr[rear] = value.
Circular Dequeue:
- Access value: value = arr[front].
- If only 1 element left (front == rear): reset pointers to -1.
- Else: increment front circularly: front = (front + 1) % MAX.