#define MAX_SIZE 6

typedef struct 	{

	  int key; } element;



element deque[MAX_SIZE];     /* global queue declaration */

int rear = -1;


void deque_empty()

{ fprintf(stderr, "The deque is empty\n");}



void deque_full()

{fprintf(stderr, "The deque is Full\n");}

void addFront(element item)

{/* add an item to the front of the dequeu */

   int i;

   if (rear == MAX_SIZE-1)

     deque_full();

   else {

      rear++;

      if (rear > 0) /* shift if deque isn't empty */

	    for (i = rear; i > 0; i--)

	        deque[i] = deque[i-1];

	  deque[0] = item;

  }

}

void addRear(element item)

{/* add an item to the high end of the global deque

     rear points to the current end of the deque */

  if (rear == MAX_SIZE-1)

     deque_full();

  else

     deque[++rear] = item;

}

element deleteFront()

{/* remove element at the front of the deque */

     int i;

	     if (rear < 0)

	     deque_empty();

     else { /* shift downward */

	     element item = deque[0];

         for (i = 1; i <= rear; i++)

		    deque[i-1] = deque[i];

		rear--;

	    return item;

	}

}

element deleteRear()

{/* remove element at the high end of the deque */

  if (rear < 0)

    deque_empty();

  else

    return deque[rear--];

}

printf("1. Add to front, 2. Delete front, 3. Add to  rear, 4. Delete rear, 0. Quit: ");

  scanf("%d",&choice);

  while (choice > 0) {

    switch  (choice) {

      case 1: printf("Enter the number to insert: ");

	      scanf("%d",&item.key);

	      addFront(item);

	      break;

      case 2: item = deleteFront();

	      if (rear >= 0)

		     printf ("%d was deleted from the queue.\n\n", item.key);

	      break;

      case 3: printf("Enter the number to insert: ");

	      scanf("%d",&item.key);

	      addRear(item);

	      break;

      case 4: item = deleteRear();

	      if (rear >= 0)

		       printf("%d was deleted from the stack \n\n",item.key);

	      break;



     }