剑指offer:面试题11、数值的整数次方

题目描述

给定一个double类型的浮点数base和int类型的整数exponent。求base的exponent次方。
保证base和exponent不同时为0

代码示例

public class Offer11 {
    public static void main(String[] args) {
        Offer11 testObj = new Offer11();
        System.out.println(testObj.power(2, 4));
        System.out.println(testObj.power(2, 5));
    }

    public double power(double base, int exp) {
        if (exp == 0) {
            return 1;
        }
        if (exp == 1) {
            return base;
        }

        boolean isNegative = false;
        if (exp < 0) {
            exp = - exp;
            isNegative = true;
        }

        double pow = power(base * base, exp / 2);
        if (exp % 2 != 0)
            pow = pow * base;
        return isNegative ? 1 / pow : pow;
    }
}