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

struct list_node {
  int data;
  struct list_node *next;
};
typedef struct list_node list_node_t;

int list_length(list_node_t * list) {
  list_node_t *cur;
  int count = 0;

  cur = list;
  while (cur != NULL) {
    count++;
    cur = cur->next;
  }

  return count;
}

void list_print(list_node_t * list) {
  list_node_t *cur;

  cur = list;
  while (cur != NULL) {
    printf("%d ", cur->data);
    cur = cur->next;
  }
  printf("\n");
}

int main(int argc, char *argv[]) {
  list_node_t *emptylist = NULL;
  assert(list_length(emptylist) == 0);
  list_print(emptylist);
  printf("list_length = %d\n", list_length(emptylist));

  list_node_t foo = { 1, NULL };
  assert(list_length(&foo) == 1);
  list_print(&foo);
  printf("list_length = %d\n", list_length(&foo));
}