public String toString() {
		StringBuilder s = new StringBuilder(sign_ > 0 ? "" : "-");

		for (int i = digits_.length - 1; i >= 0; --i) {
			s.append((char) (digits_[i] + '0'));
		}

		if (digits_.length == 0) {
			s.append('0');
		}
		return s.toString();
	}