#include <stdlib.h>
#include "stiva.h"

#define MAX 100	// dimensiunea maxima a stivei

struct _stk {
  elem_t t[MAX];	// tabloul de elemente
  int sp;		// indicele stivei
};			// avem typedef struct _stk *stack in stiva.h

stack create(void) {
 stack s = malloc(sizeof(struct _stk));
 if (s) s->sp = 0;
 return s;
}
int empty(stack s) { return s->sp == 0; }
int full(stack s) { return s->sp == MAX; }
void push(stack *s, elem_t e) { if ((*s)->sp < MAX) (*s)->t[(*s)->sp++] = e; }
elem_t pop(stack *s) { return (*s)->sp ? (*s)->t[--(*s)->sp] : 0; }
elem_t top(stack s) { return s->sp ? s->t[s->sp-1] : 0; }