剑指Offer（十二）--数值的整数次方

    public double Power(double base, int exponent) {
        if (exponent == 0) {
            // 指数为0则直接返回1
            return 1;
        }
        if (base == 0) {
            //底数为0直接返回0
            return 0;
        }
        // 判断指数是否为负数
        boolean isNegative = false;
        if (exponent < 1) {
            exponent = -exponent;
            isNegative = true;
        }
        double result;
        if (exponent % 2 == 1) {
            result = base * Power(base, exponent - 1);
        } else {
            double temp = Power(base, exponent / 2);
            result = temp * temp;
        }
        return isNegative ? (1.0 / result) : result;
    }