In java 8. Modify the averageTopSpeed() method (in the class FormulaOne) using only lambdas and streams and print it to the terminal via the driver class:

import java.util.*;

public class Racer implements Comparable { private final String name; private final int year; private final int topSpeed; public Racer(String name, int year, int topSpeed){ this.name = name; this.year = year; this.topSpeed = topSpeed; } public String toString(){ return name + "-" + year + ", Top speed: " + topSpeed + "km/h"; } public int getTopSpeed(){ return topSpeed; } public int getYear(){ return year; } public String getName(){ return name; } public int compareTo(Racer other){ if(year != other.getYear()){ return year - other.getYear(); } return name.compareTo(other.getName()); } }

public class FormulaOne { private String name; private ArrayList racers; public FormulaOne(String name){ this.name = name; racers = new ArrayList(); } public void add(Racer r){ racers.add(r); } public int averageTopSpeed(){ int sumTop = 0; int sumIt = 0; for(Racer r: racers){ sumTop += r.getTopSpeed(); sumIt++; } int avgTop = sumTop/sumIt; return avgTop;

}

public Racer fastestRacer(){ Racer fastest = null; for(Racer r: racers){ if(fastest == null || fastest.getTopSpeed() < r.getTopSpeed()){ fastest = r; } } return fastest; } public void printFormulaOne(){ System.out.println(name); Collections.sort(racers); for(Racer r: racers){ System.out.println(r); } } }

public class Driver { public static void exam(){ Racer r1 = new Racer("Farrari", 2011, 180); Racer r2 = new Racer("Lada", 2016, 320); Racer r3 = new Racer("Volvo" , 2020, 180); Racer r4 = new Racer("Fiat" , 2016, 250); Racer r5 = new Racer("Toyota", 2000, 160); System.out.println(r1.toString()); System.out.println(r2.toString()); System.out.println(r3.toString()); System.out.println(r4.toString()); System.out.println(r5.toString()); FormulaOne fo = new FormulaOne("Formula One"); fo.add(r1); fo.add(r2); fo.add(r3); fo.add(r4); fo.add(r5); System.out.println(""); System.out.println("Find average topspeed of cars in Formula One: "); System.out.println(averageTopSpeed() + "km/h"); System.out.println(""); System.out.println("Find fastest car in Formula One"); System.out.println(fo.fastestRacer()); System.out.println(""); System.out.println("Alle racerbiler i Formula One sorteres efter produktions r"); fo.printFormulaOne(); } }