#ifndef _STACK_H
#define _STACK_H

#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
    int   size;                 // maximum stack size (0 is unbounded)
};
typedef struct stack Stack;     // because we deserve nice things

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

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

Node  *peek(Stack *          ); // grab (do not disconnect) top node off stack
int    isempty(Stack *       ); // determine if the stack is empty or not
#endif