typedef struct {
  int nitems;
  int nbays;
  int max_items_on_shelves;
  int max_items_per_cust;
  int verbose;
  double cust_time;
  double robot_time;
  double duration;
  void *v;
  void *private;
}  Simulation;

typedef struct {
  int id;
  int bay;
  int *items;
  int nitems;
  double arrival_time;
  Simulation *s;
  void *v;
} Customer;

/* These are procedures which you should call */

void move_item_to_bay(Simulation *s, int item, int bay);
void customer_done(Customer *c);

/* These are procedures which you write */

void initialize_simulation(Simulation *s);
void item_stocked(Simulation *s, int item);
void new_customer(Customer *c);