public double getTip() {
        double tip = 0.00; // always initialize local variables

        switch(serviceQuality) {
            case GOOD:
                tip = bill * GOOD_RATE;
                break;
            case FAIR:
                tip = bill * FAIR_RATE;
                break;
            case POOR:
                tip = bill * POOR_RATE;
                break;
        }

        return tip;
    }