public enum Planet {
    MERKUR(3.303e+23, 2.4397e6), VENERA(4.869e+24, 6.0518e6), ZEMLJA(5.976e+24, 6.37814e6), MARS(6.421e+23, 3.3972e6),
    JUPITER(1.9e+27, 7.1492e7), SATURN(5.688e+26, 6.0268e7), URAN(8.686e+25, 2.5559e7), NEPTUN(1.024e+26, 2.4746e7);

    // gravitacijska konstanta (m3 kg-1 s-2)
    public static final double G = 6.67300E-11;
    private final double masa; // v kilogramih
    private final double radij; // v metrih

    private Planet(double masa, double radij) { // private ali nič
        this.masa = masa;
        this.radij = radij;
    }

    private double masa() {
        return masa;
    }

    private double radij() {
        return radij;
    }

    double surfaceGravity() {
        return G * masa / (radij * radij);
    }

    double surfaceWeight(double otherMass) {
        return otherMass * surfaceGravity();
    }

    public static void main(String[] args) {
        if (args.length != 1) {
            System.err.println("Uporaba: java Planet <earth_weight>, tezo podaj v kilogramih.");
            System.exit(-1);
        }
        double tezaNaZemlji = Double.parseDouble(args[0]);
        double masa = tezaNaZemlji / ZEMLJA.surfaceGravity();
        for (Planet p : Planet.values())
            System.out.printf("Tvoja teza na planetu %s je %f%n", p, p.surfaceWeight(masa));
    }

}