/*-------------------------------------------------------------------*/
/* stack.h (Version 4: Abstract Data Types)                          */
/*-------------------------------------------------------------------*/

#ifndef STACK_INCLUDED
#define STACK_INCLUDED

struct Stack
{
   double *pdArray;
   int iTop;
   int iMaxSize;
};

extern struct Stack *Stack_new(int iMaxSize);
/* Return the address of a new Stack that is able to store iMaxSize 
   items, each of type double. */

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

extern void Stack_push(struct Stack *psStack, double dItem);
/* Push dItem onto *psStack. */

extern double Stack_pop(struct Stack *psStack);
/* Pop *psStack, and return the popped item. */

extern int Stack_empty(struct Stack *psStack);
/* Return 1 (TRUE) iff *psStack is empty. */

extern int Stack_full(struct Stack *psStack);
/* Return 1 (TRUE) iff *psStack is full. */

/* 
Checked runtime errors:
   Call any function with a NULL psStack.
   Call Stack_new with iMaxSize <= 0.
   Call Stack_push with *psStack full.
   Call Stack_pop with *psStack empty.
*/

#endif