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

typedef struct stacknode {
    int element;
    struct stacknode* next;
} Node, **Stack;

Stack sCreate();
void sPush(Stack s, int element);
int sPop(Stack s);
int sEmpty(Stack s);

Stack sCreate() {
    Stack s = malloc(sizeof(Node*));
    *s = NULL;
    return s;
}

void sPush(Stack s, int element) {
    Node* n = malloc(sizeof(Node));
    n->element = element;
    n->next = *s;
    *s = n;
}

int sPop(Stack s) {
    assert(!sEmpty(s));
    Node* tmp = *s;
    *s = tmp->next;
    int element = tmp->element;
    free(tmp);
    return element;
}

int sEmpty(Stack s) {
    return (*s == NULL);
}

int main( int argc, char *argv[] ) {
	Stack s = sCreate();

    for(int i = 0; i < 10; i++) sPush(s,i);

    while(!sEmpty(s)) printf("%d\n",sPop(s));

	return 0;
}