/* File: citystk.h
 * Desc: interface of a cityPair stack ADT using an opaque type.
 * Cristina Cifuentes
 * 18 Aug 1997
 */

#ifndef _CITYSTACK_H_
#define _CITYSTACK_H_
#include "cities.h"	/* cityPair */


typedef struct _Stack *Stack;

Stack	stackNew (void);
int	stackEmpty (Stack);
void	stackPush (Stack, cityPair);
void 	stackPop (Stack, cityPair *);
void    stackFree (Stack *);

#endif