package lecture5.objects; import java.util.ArrayList; /** * This program keeps track of a list of persons names and ages. * * @author Martin Vatshelle */ public class Persons { public static void main(String[] args) { ArrayList<String> names = new ArrayList<String>(); ArrayList<Integer> ages = new ArrayList<Integer>(); fill(names, ages); printAll(names, ages); removeLast(names, ages); System.out.println(); printAll(names, ages); } /** * Persons are stored in 2 lists, * index i in names gives the name of person i and * index i in ages gives the age of person i * * This method removes the last person from the list * * @param names a list of names * @param ages a list of ages */ private static void removeLast(ArrayList<String> names, ArrayList<Integer> ages) { names.remove(names.size()-1); ages.remove(names.size()-1); } /** * Fills two lists with the same number of elements. * names.get(i) and ages.get(i) are the name and age of person i * * @param names The List of names to be filled * @param ages The List of ages to be filled */ public static void fill(ArrayList<String> names, ArrayList<Integer> ages) { names.add("Anna"); ages.add(12); names.add("Per"); ages.add(3); names.add("Hans"); ages.add(7); names.add("Lise"); ages.add(9); } /** * Prints out the names and ages of a list of Persons * * @param names * @param ages */ public static void printAll(ArrayList<String> names, ArrayList<Integer> ages) { for(int i=0; i<names.size(); i++) { System.out.println(names.get(i)+" is "+ ages.get(i)+" years."); } } }