Rozwiązanie
import javax.swing.*; public class Town { private String[] town = { "Warszawa", "Poznań", "Kraków", "Gdańsk" }; Town() { show("Na początku"); exchange(0, town.length -1); show("Po przestawienieu pierwszego i ostatniego"); exchange(1,2); show("Po przestawienieu drugiego i trzeciego"); String s = JOptionPane.showInputDialog("Podaj nazwc miasta"); if (s != null) { String msg = "Nie ma takiego miasta"; int ind = getIndex(s); if (ind != -1) msg = "Miasto " + s + " indeks " + ind; System.out.println(msg); } System.exit(0); } public void show(String s) { System.out.println(s); for (int i=0; i<town.length; i++) System.out.println(town[i]); } public void exchange(int first, int last) { String temp = town[last]; town[last] = town[first]; town[first] = temp; } public int getIndex(String s) { for (int i=0; i<town.length; i++) if (town[i].equals(s)) return i; return -1; } public static void main(String[] args) { new Town(); } }