/* * File: queue.h * ------------- * This file provides an interface to a simple queue * abstraction. */#ifndef _queue_h#define _queue_h#include "genlib.h"/* * Type: queueADT * -------------- * This line defines the abstract queue type as a pointer to * its concrete counterpart.  Clients have no access to the * underlying representation. */typedef struct queueCDT *queueADT;/* * Function: NewQueue * Usage: queue = NewQueue(); * -------------------------- * This function allocates and returns an empty queue. */queueADT NewQueue(void);/* * Function: FreeQueue * Usage: FreeQueue(queue); * ------------------------ * This function frees the storage associated with queue. */void FreeQueue(queueADT queue);/* * Function: Enqueue * Usage: Enqueue(queue, obj); * --------------------------- * This function adds obj to the end of the queue. */void Enqueue(queueADT queue, void *obj);/* * Function: Dequeue * Usage: obj = Dequeue(queue); * ---------------------------- * This function removes the data value at the head of the queue * and returns it to the client.  Dequeueing an empty queue is * an error. */void *Dequeue(queueADT queue);/* * Function: QueueLength * Usage: n = QueueLength(queue); * ------------------------------ * This function returns the number of elements in the queue. */int QueueLength(queueADT queue);#endif