/*--------------------------------------------------------------------*/
/* stack.h (Version 1)                                                */
/* Author: Bob Dondero                                                */
/*--------------------------------------------------------------------*/

#ifndef STACK_INCLUDED
#define STACK_INCLUDED

/* A Stack object is a last-in-first-out collection of doubles. */
struct Stack
{
   /* The array in which items are stored. */
   double *pdArray;

   /* The index one beyond the top element. */
   int iTop;

   /* The number of elements in the array. */
   int iPhysLength;
};

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

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

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

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

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

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

#endif