#include <stdio.h>
#include <stdlib.h>
#define SIZE 5  // Define the size of the queue

typedef struct {
    int items[SIZE];
    int front, rear;
} CircularQueue;

// Function to initialize the queue
void initializeQueue(CircularQueue *q) {
    q->front = -1;
    q->rear = -1;
}

// Check if the queue is full
int isFull(CircularQueue *q) {
    return ((q->rear + 1) % SIZE == q->front);
}

// Check if the queue is empty
int isEmpty(CircularQueue *q) {
    return (q->front == -1);
}

// Enqueue operation
void enqueue(CircularQueue *q, int value) {
    if (isFull(q)) {
        printf("Queue is full! Cannot enqueue %d\n", value);
        return;
    }
    if (isEmpty(q)) {
        q->front = 0;
    }
    q->rear = (q->rear + 1) % SIZE;
    q->items[q->rear] = value;
    printf("Enqueued: %d\n", value);
}

// Dequeue operation
int dequeue(CircularQueue *q) {
    if (isEmpty(q)) {
        printf("Queue is empty! Cannot dequeue.\n");
        return -1;
    }
    int data = q->items[q->front];
    if (q->front == q->rear) {
        // Queue becomes empty
        q->front = -1;
        q->rear = -1;
    } else {
        q->front = (q->front + 1) % SIZE;
    }
    printf("Dequeued: %d\n", data);
    return data;
}

// Display the queue visually
void display(CircularQueue *q) {
    if (isEmpty(q)) {
        printf("Queue is empty!\n");
        return;
    }
    printf("Circular Queue: [ ");
    for (int i = 0; i < SIZE; i++) {
        if ((q->front <= q->rear && (i >= q->front && i <= q->rear)) ||
            (q->front > q->rear && (i >= q->front || i <= q->rear))) {
            printf("%d ", q->items[i]);
        } else {
            printf("_ ");
        }
    }
    printf("]\n");
}

// Menu to choose operations
void menu() {
    printf("\nChoose an operation:\n");
    printf("1. Enqueue\n");
    printf("2. Dequeue\n");
    printf("3. Display Queue\n");
    printf("4. Exit\n");
    printf("Enter your choice: ");
}

int main() {
    CircularQueue q;
    initializeQueue(&q);
    int choice, value;

    while (1) {
        menu();
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                printf("Enter value to enqueue: ");
                scanf("%d", &value);
                enqueue(&q, value);
                display(&q);
                break;

            case 2:
                dequeue(&q);
                display(&q);
                break;

            case 3:
                display(&q);
                break;

            case 4:
                printf("Exiting...\n");
                exit(0);

            default:
                printf("Invalid choice! Please try again.\n");
        }
    }

    return 0;
}