---

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

struct stack_node *init(int value) {
    struct stack_node *node = (struct stack_node *)malloc(sizeof(struct stack_node));

    if (node != NULL) {
        node->value = value;
        node->next = NULL;
    }

    return node;
}

struct stack_node *push(struct stack_node *root, int value) {
    struct stack_node *new_node = init(value);

    if (new_node != NULL) {
        new_node->next = root;
    }

    return new_node;
}

struct stack_node *pop(struct stack_node *root) {
    struct stack_node *new_root = NULL;

    if (root != NULL) {
        new_root = root->next;
        free(root);
    }

    return new_root;
}

void destroy(struct stack_node *root) {
    struct stack_node *current = root;
    struct stack_node *next_node;

    while (current != NULL) {
        next_node = current->next;
        free(current);
        current = next_node;
    }
}