package Q13_07_Lambda_Expressions;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Stream;
public class QuestionC {
public static int getPopulation(List<Country> countries, String continent) {
Stream<Integer> populations = countries.stream().map(c ->
c.getContinent().equals(continent) ? c.getPopulation() : 0);
return populations.reduce(0, (a, b) -> a + b);
}
public static void main(String... args) {
ArrayList<Country> countries = new ArrayList<Country>();
countries.add(new Country("United States", "North America", 5));
countries.add(new Country("Canada", "North America", 10));
countries.add(new Country("India", "Asia", 30));
System.out.println(getPopulation(countries, "North America"));
}
}