@Override
    public String toString()
    {
        StringBuilder sb = new StringBuilder(digits.length + 1);
        if (isNegative) {
            sb.append("-");
        }
        boolean first = false;
        for (int ii = digits.length - 1; ii >= 0; ii--) {
            // Strip leading zeros, unless zero is the only digit.
            if (digits[ii] == 0 && !first && ii != 0) {
                continue;
            }
            sb.append(Integer.toString(digits[ii]));
            first = true;
        }
        return sb.toString();
    }