module observer.heatindexdisplay; import observer.displayelement; import observer.observer; import observer.weatherdata; import std.stdio : writeln; class HeatIndexDisplay : Observer, DisplayElement { private: float heatIndex; WeatherData weatherData; float computeHeatIndex(float t, float rh) { return ((16.923 + (0.185212 * t) + (5.37941 * rh) - (0.100254 * t * rh) + (0.00941695 * (t * t)) + (0.00728898 * (rh * rh)) + (0.000345372 * (t * t * rh)) - (0.000814971 * (t * rh * rh)) + (0.0000102102 * (t * t * rh * rh)) - (0.000038646 * (t * t * t)) + (0.0000291583 * (rh * rh * rh)) + (0.00000142721 * (t * t * t * rh)) + (0.000000197483 * (t * rh * rh * rh)) - (0.0000000218429 * (t * t * t * rh * rh)) + 0.000000000843296 * (t * t * rh * rh * rh)) - (0.0000000000481975 * (t * t * t * rh * rh * rh))); } public: this(WeatherData weatherData) { weatherData.registerObserver(this); } override void update(float temperature, float humidity, float pressure) { this.heatIndex = computeHeatIndex(temperature, humidity); display(); } override void display() { writeln("Heat index is ", heatIndex); } }