linearqueue.c

#include <stdio.h>
#define SIZE 5

int queue[SIZE], front = -1, rear = -1;

void enqueue(int value) {
    if (rear == SIZE - 1) {
        printf("Queue Overflow\n");
    } else {
        if (front == -1)
            front = 0;
        rear++;
        queue[rear] = value;
    }
}


void dequeue() {
    
    if (front == -1) {
        printf("Queue Underflow\n");
    } else {
        printf("Dequeued: %d\n", queue[front]);
        if (front == rear)
            front = rear = -1;
        else
            front++;
        
    }
}

void display() {
    if (front == -1) {
        printf("Queue is empty\n");
    } else {
        for (int i = front; i <= rear; i++)
            printf("%d ", queue[i]);
        printf("\n");
    }
}

int main() {
    int choice, value;

    while (1) {
        printf("\n1. Enqueue\n2. Dequeue\n3. Display\n4. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        if (choice == 1) {
            printf("Enter value: ");
            scanf("%d", &value);
            enqueue(value);
            
        } else if (choice == 2) {
            dequeue();
            
        } else if (choice == 3) {
            display();
            
        } else if (choice == 4) {
            printf("Exiting...\n");
            break;
            
        } else {
            printf("Invalid choice\n");
        }
    }

    return 0;
}