(front + size / 2) % capacity

public class CircularQueue {
    private int[] queue;
    private int front, rear, size, capacity;

    public CircularQueue(int capacity) {
        this.capacity = capacity;
        this.queue = new int[capacity];
        this.front = 0;
        this.rear = 0;
        this.size = 0;
    }

    public boolean isFull() {
        return size == capacity;
    }

    public boolean isEmpty() {
        return size == 0;
    }

    public void enqueue(int data) {
        if (isFull()) {
            throw new RuntimeException("Queue is full");
        }
        queue[rear] = data;
        rear = (rear + 1) % capacity;
        size++;
    }

    public int dequeue() {
        if (isEmpty()) {
            throw new RuntimeException("Queue is empty");
        }
        int data = queue[front];
        front = (front + 1) % capacity;
        size--;
        return data;
    }

    public int getMiddle() {
        if (isEmpty()) {
            throw new RuntimeException("Queue is empty");
        }
        int middleIndex = (front + size / 2) % capacity;
        return queue[middleIndex];
    }

    public static void main(String[] args) {
        CircularQueue cq = new CircularQueue(5);
        cq.enqueue(10);
        cq.enqueue(20);
        cq.enqueue(30);
        cq.enqueue(40);
        cq.enqueue(50);
        
        System.out.println("Middle element: " + cq.getMiddle());  // Output: Middle element: 30
        
        cq.dequeue();
        cq.enqueue(60);
        
        System.out.println("Middle element: " + cq.getMiddle());  // Output: Middle element: 40
    }
}