/*-------------------------------------------------------------------*/
/* stackao.h (A Stack Abstract Object Interface)                     */
/*-------------------------------------------------------------------*/

#ifndef STACKAO_INCLUDED
#define STACKAO_INCLUDED

void Stack_init(void);
/* Initialize the Stack.
   It is a checked runtime error for the Stack to be initialized. */

void Stack_free(void);
/* Free the resources consumed by the Stack.
   It is a checked runtime error for the Stack to be uninitialized. */

void Stack_push(double dItem);
/* Push dItem onto the Stack.
   It is a checked runtime error for the Stack to be uninitialized. */

double Stack_pop(void);
/* Pop the Stack, and return the popped item.
   It is a checked runtime error for the Stack to be uninitialized or
   empty. */

int Stack_isEmpty(void);
/* Return 1 (TRUE) iff the Stack is empty.
   It is a checked runtime error for the Stack to be uninitialized. */

#endif