_hashCode = _first==null?0:_first.hashCode(); _hashCode += _second==null?0:_second.hashCode();
_hashCode = _first.hashCode();
    public Complex( Object o1, Object o2 ) {        _size = 2;        _first = o1;        _second = o2;        _all = null;        _hashCode = _first==null?0:_first.hashCode();        _hashCode += _second==null?0:_second.hashCode();    }