IteratorTest.java

public class IteratorTest {
  public static void main(String[] args) {
    Collection<Integer> l = new LinkedList<Integer>();
    l.add(1);
    l.add(2);
    l.add(5);
    System.out.println(average(l));
    System.out.println(countInRange(l, 0, 3));
  }
  
  public static float average(Collection<Integer> l) {
    
    int sum = 0;
    
    /*
    for (int i = 0; i < l.size(); i++) {
      sum += (Integer) l.get(i); 
    }
    */
    /*
    Iterator it = l.iterator();
    while (it.hasNext()) {
      sum += (Integer) it.next();  
    }
    */
    for (Integer i : l) {
      sum += i;
    }
    return sum / l.size();
  }
  
  public static int countInRange(Collection<Integer> l, int lo, int hi) {
    int count = 0;
    Iterator it = l.iterator();
    while (it.hasNext()) {
      int curr = (Integer) it.next();
      count += (lo <= curr && curr <= hi) ? 1 : 0;  
    }
    /*
    for (int i = 0; i < l.size(); i++) {
      int curr = (Integer) l.get(i);
      if (lo <= curr && curr <= hi) {
        count++;
      }
    }
    */
    return count;
  }
  
}