public class Barometer {
    private double pressure;
    
    /**
     * A Barometer with air pressure p (in kPa).
     */
    public Barometer(double p) {
        pressure = p;
    }
    
    /**
     * = "this Barometer has the same air pressure as b 
     * (to within 0.1 kPa)."
     */
    public boolean equals(Barometer b) {
        return b != null && Math.abs(pressure - b.pressure) <= 0.1;
    }
    
}