MIT-Curricular/DS/C/Lab/Week4/circq.c

#include <stdio.h>

#define MAX_SIZE 4

int queue[MAX_SIZE];
int front = 0;
int rear = 0;

void enqueue(int data) {
    if ((rear + 1) % MAX_SIZE == front) {
        printf("\n\nQueue is full\n\n\n");
        return;
    }
    queue[rear] = data;
    rear = (rear + 1) % MAX_SIZE;
}

int dequeue() {
    if (front == rear) {
        printf("Queue is empty\n");
        return -1;
    }
    int data = queue[front];
    front = (front + 1) % MAX_SIZE;
    return data;
}

void printQueue() {
    if (front == rear) {
        printf("Queue is empty\n");
        return;
    }
    int i = front;
    while (i != rear) {
        printf("%d ", queue[i]);
        i = (i + 1) % MAX_SIZE;
    }
    printf("\n");
}

int main() {
    int choice, data;
    while (1) {
        printf("Choose the Circular Queue option you would like to perform:\n");
        printf("1. Enqueue\n2. Dequeue\n3. Print Queue\n4. Exit\n");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                printf("Enter the value for the latest element: ");
                scanf("%d", &data);
                enqueue(data);
                break;
            case 2:
                data = dequeue();
                if (data != -1) printf("Dequeued: %d\n", data);
                break;
            case 3:
                printQueue();
                break;
            case 4:
                return 0;
            default:
                printf("Invalid choice.");
                return -1;
        }
    }
}