classDiagram
    class WeatherData {
        getTemperature()
        getHumidity()
        getPressure()
        measurementsChanged()

        subscribe(observer: IWeatherObserver)
        unsubscribe(observer: IWeatherObserver)
        notify(data: WeatherRecord)
    }
    class WeatherRecord {
        f32 temperature
        f32 humidity
        f32 pressure
    }
    class IWeatherObserver {
        update(data: WeatherRecord)
    }
    class IWeatherSubject {
        subscribe(observer: IWeatherObserver)
        unsubscribe(observer: IWeatherObserver)
        notify(data: WeatherRecord)
    }
    class WeatherScreen1 {
        update(data: WeatherRecord)
        draw()
    }
    IWeatherSubject <|.. WeatherData
    IWeatherObserver <|.. WeatherScreen1
    IWeatherObserver <-- IWeatherSubject : observers
    WeatherData <-- WeatherScreen1 : Subjects
    IWeatherObserver .. IWeatherSubject
    class IDisplayElement {
        draw()
    }
    IDisplayElement <|.. WeatherScreen1