Deletion in a Queue in C

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

#define MAX 50			//defining the size of queue

int queue[MAX], front = 0, rear = -1, itemCount = 0;

bool isEmpty ()
{
  return itemCount == 0;
}

bool isFull ()
{
  return itemCount == MAX;
}

void enqueue (int data)
{

  if (!isFull ())
    {

      if (rear == MAX - 1)
	{
	  rear = -1;
	}

      queue[++rear] = data;
      itemCount++;
    }
}

void display ()			//function to display the relents of the queue
{
  printf ("The elements in the queue are:");
  int i;
  if (isEmpty ())
    printf (" Queue is Empty");
  else
    for (i = front; i <= rear; i++)
      {

	printf ("%d ", queue[i]);
      }
  printf ("\n");
}

void dequeue ()			//function to delete elements from the queue
{
  if (isEmpty ())
    printf (" Queue is Empty");
  else
    {
      queue[front] = 0;
      front = front + 1;
      itemCount--;
    }
  display ();
}

int queuesize ()
{
  return itemCount;
}

int main ()				
{

  enqueue (3);
  enqueue (5);
  enqueue (9);
  enqueue (1);
  enqueue (12);
  enqueue (15);
  
  int size = queuesize ();

  display ();
  printf ("\nDequeuing elements:\n");
  
  for (int i = 0; i < size; i++)
    {
      dequeue ();
    }

}