EXP2b.txt

#include <stdio.h>
#include <stdlib.h>

#define MAX 5

// Queue structure
static int queue[MAX];
int front = -1;
int rear = -1;

// Function to insert an element into the queue
void insert(int x) {
    if ((rear + 1) % MAX == front) { // Check for full condition
        printf("\nQueue Full\n");
        return;
    }

    // If queue is empty, initialize front and rear
    if (front == -1) {
        front = 0;
    }
    
    rear = (rear + 1) % MAX; // Circular increment
    queue[rear] = x;
    printf("\n%d inserted into the queue\n", x);
}

// Function to remove an element from the queue (renamed from remove to dequeue)
int dequeue() {
    if (front == -1) { // Check for empty condition
        printf("\nQueue Empty\n");
        return -1; // Return an invalid value
    }
    
    int val = queue[front];
    if (front == rear) {
        // Queue is now empty after this removal
        front = rear = -1;
    } else {
        front = (front + 1) % MAX; // Circular increment
    }
    return val;
}

// Function to view the elements in the queue
void view() {
    if (front == -1) {
        printf("\nQueue Empty\n");
    } else {
        printf("\nFront --> ");
        int i = front;
        while (1) {
            printf("%4d", queue[i]);
            if (i == rear) break; // Stop when we reach the rear
            i = (i + 1) % MAX; // Circular increment
        }
        printf(" <-- Rear\n");
    }
}

// Main function to drive the queue operations
int main() {
    int choice = 0, val;

    while (choice != 4) {
        printf("\nQUEUE OPERATIONS\n");
        printf("1. INSERT\n");
        printf("2. DELETE\n");
        printf("3. VIEW\n");
        printf("4. QUIT\n");
        printf("Enter Choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                printf("Enter element to be inserted: ");
                scanf("%d", &val);
                insert(val);
                break;
            case 2:
                val = dequeue();  // Changed from remove() to dequeue()
                if (val != -1) {
                    printf("Element deleted: %d\n", val);
                }
                break;
            case 3:
                view();
                break;
            case 4:
                printf("Exiting...\n");
                exit(0);
            default:
                printf("\nInvalid Choice\n");
        }
    }
    return 0;
}