// The ArrayIntListIterator class provides a set of utilities for iterating
// over an ArrayIntList and possibly removing values from the list.

import java.util.*;

public class ArrayIntListIterator implements Iterator<Integer> {
    private ArrayIntList list;      // list to iterate over
    private int position;           // current position within the list
    private boolean removeOK;       // whether it's okay to remove now

    // pre : list != null
    // post: constructs an iterator for the given list
    public ArrayIntListIterator(ArrayIntList list) {
	this.list = list;
	position = 0;
	removeOK = false;
    }

    // post: returns true if there are more elements left, false otherwise
    public boolean hasNext() {
	return position < list.size();
    }

    // pre : hasNext()
    // post: returns the next element in the iteration
    public Integer next() {
	if (!hasNext())
	    throw new NoSuchElementException();
	int result = list.get(position);
	position++;
	removeOK = true;
	return result;
    }

    // pre : next() has been called without a call on remove (i.e., at most one
    //       call per call on next)
    // post: removes the last element returned by the iterator
    public void remove() {
	if (!removeOK)
	    throw new IllegalStateException();
	list.remove(position - 1);
	position--;
	removeOK = false;
    }
}