code: @Override
    public boolean removeAll(IntSet c)
    {
      if (c == null || c.isEmpty()) {
        return false;
      }
      IntIterator itr;
      if (c instanceof HashIntSet) {
        itr = ((HashIntSet) c).unsortedIterator();
      } else {
        itr = c.iterator();
      }
      boolean res = false;
      while (itr.hasNext()) {
        res |= remove(itr.next());
      }
      return res;
    }
docs: {@inheritDoc}