/* lqueue.h */

#ifndef __lqueue_h
#define __lqueue_h


typedef struct node_t {
  int value;
  struct node_t *next;
  struct node_t *prev;
} Node;

typedef struct queue_t {
  Node* head;
  Node* tail;
} Queue; 

/* create and return an empty q */
Queue *qCreate(); 

/* destroys the q */
void qDestroy(Queue *qh); 

/* print all values in the q in the order in which they appear  */
void qPrint(Queue *qh);

/* create a new node with value=key and insert it in the q */
void qEnq(Queue *qh, int key); 

/*  */
Node *qHead(Queue *qh); 

void qDelete(Queue *qh, Node *node);

#endif