#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

typedef struct node {
    void *content;
    struct node *next;
}Node;

typedef struct stack {
    Node *top;
    size_t w;
}Stack;

Stack *new_stack(size_t w) {
    Stack *s = malloc(sizeof(Stack));
    s->top = NULL;
    s->w = w;
    return s;
}

bool is_empty(Stack *s) {
    return !s->top;
}

void push(void *content, Stack *s) {
    Node *n = malloc(sizeof(Node));
    n->content = malloc(s->w);
    mempcpy(n->content, content, s->w);
    n->next = s->top;
    s->top = n;
}

void *pop(Stack *s) {
    if (is_empty(s))
        return NULL;
    void *r = s->top->content;
    Node *n = s->top;
    s->top = s->top->next;
    free(n);
    return r;
}

void destroy(Stack *s) {
    while (!is_empty(s)) {
        free(s->top->content);
        pop(s);        
    }
}

int main() {
    Stack *s = new_stack(sizeof(int));
    int *a = malloc(sizeof(int));
    int *b = malloc(sizeof(int));
    int *c = malloc(sizeof(int));
    int *d = malloc(sizeof(int));
    *a=1;
    *b=2;
    *c=3;
    *d=-1;
    push(a, s);
    push(b, s);
    push(c, s);
    push(d, s);
    destroy(s);
    printf("%d\n", is_empty(s));
    return 0;
}