package headfirst.observer.weather;import java.util.*;public class StatisticsDisplay implements Observer, DisplayElement {	private float maxTemp = 0.0f;	private float minTemp = 200;	private float tempSum= 0.0f;	private int numReadings;	private WeatherData weatherData;	public StatisticsDisplay(WeatherData weatherData) {		this.weatherData = weatherData;		weatherData.registerObserver(this);	}	public void update(float temp, float humidity, float pressure) {		tempSum += temp;		numReadings++;		if (temp > maxTemp) {			maxTemp = temp;		} 		if (temp < minTemp) {			minTemp = temp;		}		display();	}	public void display() {		System.out.println("Avg/Max/Min temperature = " + (tempSum / numReadings)			+ "/" + maxTemp + "/" + minTemp);	}}