/* stack4.c */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "stack4.h"

struct stack
{
    int size;
    int *data;
    int ptr;
};

Stack *stack_create(int size)
{
/* Same as in stack3.c... */
}

int stack_push(Stack *stkp, int x)
{
/* Same as in stack3.c... */
}

int stack_pop(Stack *stkp)
{
/* Same as in stack3.c... */
}

void stack_destroy(Stack *stkp)
{
/* Same as in stack3.c... */
}
