public class Bilprogram {
    public static void main(String[] args) {
        Kjoretoy kjt = new Sportsbil("ABC123", "audi", 100);
        Bil bil = new Bil();
        Sportsbil spb = null;

        if (bil instanceof Sportsbil) {
            spb = (Sportsbil) kjt;
            spb.skrivUt();
        } else {
            System.out.println("Kunne ikke caste");
        }
    }
}