typedef struct queue *Queue;
typedef int Item;

/** Create a new, empty Queue */
Queue QueueNew(void);

/** Free memory allocated to a Queue */
void QueueFree(Queue q);

/** Add an item to the end of a Queue */
void QueueEnqueue(Queue q, Item it);

/** Remove an item from the front of a Queue
Assumes that the Queue is not empty */
Item QueueDequeue(Queue q);

/** Get the number of items in a Queue */
int QueueSize(Queue q);

/** Get the item at the front of a Queue
Assumes that the Queue is not empty */
Item QueuePeek(Queue q);