#ifndef _STACK_H
#define _STACK_H

#include "data.h"                    // helpful #defines
#include "list.h"                    // stack relies on list to work
                                     // (which relies on node)

struct stack {
    List             *data;          // pointer to list containing data
    Node             *top;           // pointer to node at top of stack
    uli               size;          // maximum stack size (0 implies
};                                   // an unbounded stack)
typedef struct stack  Stack;         // because we deserve nice things

code_t mkstack(Stack **, uli);       // create new stack (of max size)
code_t cpstack(Stack *, Stack **);   // create a copy of an existing stack
code_t rmstack(Stack **);            // clear and de-allocate an existing stack

code_t push(Stack **, Node * );      // put new node on top of stack
code_t pop (Stack **, Node **);      // get (and disconnect) top node off stack

code_t peek(Stack *,  Node **);      // get (don't disconnect) top node
code_t isempty(Stack *);             // determine if the stack is empty or not
#endif