In Java, you cannot directly write the executable statements in class. You need to move your code in a method. Only variables declaration is allowed outside the method/blocks. Just for the sake of testing, ,move everthing to main method. Try this:
public class Orders { public static void main(String argsp[]) { String alphabet = "abc"; ArrayList<String> list = new ArrayList<String>(); int n = alphabet.length(); Random rand = new Random(); for (int i = 0; i < 10000; i++){ char a = alphabet.charAt(rand.nextInt(n)); char b = alphabet.charAt(rand.nextInt(n)); char c = alphabet.charAt(rand.nextInt(n)); String s = Character.toString(a) + Character.toString(b) + Character.toString(c); if(list.indexOf(s) == -1){ list.add(s); } } System.out.println(list); } }
Note: system.out.println(arrayList);
will throw an error because there is no varaible called arrayList
, i think it should be replaced with variable list
. Also system
should be System
.