stack

// not finnished

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

typedef struct node {
    int data;
    struct node *next;
} stack;

stack* init() {
    stack* tmp = malloc(sizeof(stack));
    tmp->data = NULL;
    tmp->next = NULL;
    return tmp;
}

void destroy(stack **s) {
    *s = NULL;
}

int push(stack** s, int value) {
    if (s == NULL) return 0;

    if((*s)->data == NULL) {
        (*s)->data = value;
    }
    else {
        stack* tmp = malloc(sizeof(stack));
        tmp->data = value;
        tmp->next = *s;
        *s = tmp;
    }

    return 1;
}

int pop(stack** s) {
    if (s == NULL) return NULL;
    int value = (*s)->data;
    *s = (*s)->next;

    return value;
}

int main() {
    stack* st1 = init();
    push(&st1, 1);
    push(&st1, 2);

    //push(st1, 3);
    printf("%d\n", st1->data);
    pop(&st1);
    printf("%d\n", st1->data);
    //destroy(st1);
}