ForecastDisplayWithEventsAndDelegates.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HeadFirstDesignPatterns.Ch02TheObserverPattern.WeatherStationWithEventsAndDelegates
{
    class ForecastDisplayWithEventsAndDelegates : IObserverWithEventsAndDelegates, DisplayElementWithEventsAndDelegates
    {
        private float currentPressure = 29.92F;
        private float lastPressure;

        public void Update(float temperature, float humidity, float pressure)
        {
            lastPressure = currentPressure;
            currentPressure = pressure;

            Display();
        }

        public void Display()
        {
            System.Console.WriteLine("Forecast: ");
            if (currentPressure > lastPressure)
            {
                System.Console.WriteLine("Improving weather on the way!");
            }
            else if (currentPressure == lastPressure)
            {
                System.Console.WriteLine("More of the same");
            }
            else if (currentPressure < lastPressure)
            {
                System.Console.WriteLine("Watch out for cooler, rainy weather");
            }
        }
    }
}