//: c12:MutableInteger.java // From Thinking in Java, 2nd Edition // Available at http://www.BruceEckel.com // (c) Bruce Eckel 1999 // Copyright notice in Copyright.txt // A changeable wrapper class import java.util.*; class IntValue { int n; IntValue(int x) { n = x; } public String toString() { return Integer.toString(n); } } public class MutableInteger { public static void main(String[] args) { ArrayList v = new ArrayList(); for(int i = 0; i < 10; i++) v.add(new IntValue(i)); System.out.println(v); for(int i = 0; i < v.size(); i++) ((IntValue)v.get(i)).n++; System.out.println(v); } } ///:~