import java.io.*;
import java.util.ArrayList;

public class Test {
    public static void main(String[] args){
        Car test = new Car();
        Trailer t = new Trailer(80,60);
        RoadTrain r = new RoadTrain(60,45);

        ArrayList<Car> cars = new ArrayList<>();
        cars.add(t);
        cars.add(r);

        System.out.println("Max speed: " + test.maxSpeed(t,r));
        System.out.println("Min radius: " + test.minRadius(t,r));
        try{
            Test.save(cars);
        } catch (IOException e) {}
        try{
            Test.read(cars);
        } catch (IOException e){

        } catch (ClassNotFoundException e) {}
    }

    public static void save(ArrayList<Car> cars) throws IOException{
        FileOutputStream fos = new FileOutputStream("temp.out");
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        for(Car car : cars){
            oos.writeObject(car);
            oos.flush();
        }
        oos.close();
    }

    public static void read(ArrayList<Car> cars) throws IOException, ClassNotFoundException {
        FileInputStream fis = new FileInputStream("temp.out");
        ObjectInputStream oin = new ObjectInputStream(fis);
        for(Car car : cars){
            Car c = (Car) oin.readObject();
            cars.add(c);
        }
    }

    public static class Trailer extends Car implements Serializable{
            public Trailer(int a, int b){
                this.setSpeed(a);
                this.setRadius(b);
            }
        }

    public static class RoadTrain extends Car implements Serializable{
            public RoadTrain(int a, int b){
                this.setSpeed(a);
                this.setRadius(b);
            }
        }

    public static class Car{
        private int permissible_speed = 0;
        private int minimum_turning_radius = 0;

        public int getSpeed(){
            return permissible_speed;
        }
        public int getRadius(){
            return minimum_turning_radius;
        }
        public void setSpeed(int s){
            if(s > 0 ) this.permissible_speed = s;
            else System.out.println("Error");
        }
        public void setRadius(int r){
            if(r > 0 && r < 180) this.minimum_turning_radius = r;
            else System.out.println("Error");
        }
        public int maxSpeed(Car a, Car b){
            if (a.getSpeed() > b.getSpeed()) return a.getSpeed();
            else return b.getSpeed();
        }
        public int minRadius(Car a, Car b){
            if (a.getRadius() > b.getRadius()) return b.getRadius();
            else return a.getRadius();
        }
    }
}