/*--------------------------------------------------------------------*/
/* stack.h (Version 2)                                                */
/* Author: Bob Dondero                                                */
/*--------------------------------------------------------------------*/

#ifndef STACK_INCLUDED
#define STACK_INCLUDED

struct Stack;
/* A struct Stack is a last-in-first-out collection of doubles. */

struct Stack *Stack_new(void);
/* Return the address of a new Stack object, or NULL if insufficient
   memory is available. */

void Stack_free(struct Stack *psStack);
/* Free psStack. */

int Stack_push(struct Stack *psStack, double dItem);
/* Push dItem onto *psStack.  Return 1 (TRUE) if successful, or 0
   (FALSE) if insufficient memory is available. */

double Stack_top(struct Stack *psStack);
/* Return the top item of *psStack. */

void Stack_pop(struct Stack *psStack);
/* Pop and discard the top item of *psStack. */

int Stack_isEmpty(struct Stack *psStack);
/* Return 1 (TRUE) if *psStack is empty, or 0 (FALSE) otherwise. */

#endif