Enqueue Dequeue in C

#include <stdio.h>
#include <conio.h>
#include <windows.h>
#define MAX 100
struct queue
{
    int item[MAX];
    int front, rear;
};
typedef struct queue queue;

void enqueue (queue *q, int a)
{
    if (q->rear == MAX - 1)
    printf("Queue is full.\n");

    else if (q->rear == -1)
    {
        (q->rear)++;
        (q->front)++;
        q->item[q->rear] = a;
    }
    else
    {
        (q->rear)++;
        q->item[q->rear] = a;
    }
}

int dequeue (queue *q)
{
    int elt = 0;
    if(q->front== -1 || q->front > q->rear)
    printf("Queue is empty.\n");

    else
    {
        elt = q -> item [q -> front];
        (q->front)++;
    }
    return elt;
}

void traverse (queue *q)
{
    int i;
    for(i=q->front; i<=q->rear; i++)
    {
        printf("%d\t", q -> item[i]);
    }
}

int main()
{
    queue q;
    q.rear = -1;
    q.front = -1;
    int el,ch;
    while(1)
    {
        printf("\n\n1.Enqueue\n");
        printf("2.Dequeue\n");
        printf("3.Display all\n");
        printf("4.Exit\n\n");
        printf("Enter choice:");
        scanf("%d",&ch);
        switch(ch)
        {
            case 1:
                printf("Enter element you want to Enqueue");
                scanf("%d",&el);
                enqueue(&q,el);
                break;

            case 2:
                el=dequeue(&q);
                printf("%d is Dequeued from the stack",el);
                break;

            case 3:
                traverse(&q);
                break;

            case 4:
                exit(0);

            default:
                printf("Invalid choice.");
        }
    }
}