>>280
int pop(void)
{
struct node *n = TOP.next;

if (n == NULL) {
fprintf(stderr, "no stack\n");
return 0;
}
else {
int num = n->key;
TOP.next = n->next;
free(n);
return num;
}
}

int main(void)
{
TOP.next = NULL;

push(21);
push(42);

printf("%d\n", pop());
printf("%d\n", pop());

return 0;
}