Reverses a linked list

rev.c

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

// --- stack library functions ---

// typedefs to keep things more semantic
typedef struct stack_s Stack;
typedef Stack node_t;

struct stack_s {
  Stack* next;
  int data;
};

// Create and delete the underlying datastructure
size_t count = 0;
Stack* init() {
  Stack* stack = malloc(sizeof(Stack));
  stack->next = NULL;
  stack->data = count++;
  return stack;
}
void deinit(Stack* stack) {
  if (!stack) return;
  node_t* next = stack->next;
  free(stack);
  deinit(next);
}

// Utility functions
bool is_empty(Stack** stack) {
  return !(*stack)->next;
}
void print(Stack* stack) {
  for (; stack && stack->next; stack = stack->next) {
    printf("%d -> ", stack->data);
  }
  printf("X\n");
}

// Core stack operations
void push(Stack** stack, node_t* node) {
  node->next = *stack;
  *stack = node;
}
Stack* pop(Stack** stack) {
  if (is_empty(stack)) return NULL;

  node_t* result = *stack;
  *stack = (*stack)->next;

  return result;
}

void rev(Stack** stack) {
  Stack* temp = init();
  while (!is_empty(stack)) {
    push(&temp, pop(stack));
  }
  deinit(*stack);
  *stack = temp;
}

// --- tests ---

int main() {
  Stack* stack = init();
  push(&stack, init());
  push(&stack, init());
  push(&stack, init());

  print(stack);
  rev(&stack);
  print(stack);
}