class Vehicle {
public:

  void move(Position new_position);
  Position current_position;
  void accelerate(int new_speed);
  int current_speed;

};

class Car : public Vehicle {
public:
  void steer(int new_heading);
  int current_heading;
};

class Train : public Vehicle {
public:
  void direction(new_direction)
  int current_direction;
};

class Airplane : public Vehicle {
public:
  void steer(int new_heading);
  int current_heading;
  void climb(int new_altitude);
  int current_altitude;
};