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。

class Solution {
public:
    bool g_InvalidInput = false;
    double Power(double base, int exponent) {
        g_InvalidInput = false;
        if(base == 0.0 && exponent<0){
            g_InvalidInput = true;
            return 0.0;
        }
        
        unsigned int absExponent = (unsigned int)(exponent);
        if(exponent < 0)
                absExponent = (unsigned int)(-exponent);
        
        double result = PowerWithUnsignedExponent(base,absExponent);
        if(exponent < 0)
            result = 1.0/result;
        return result;
    }
    
    double PowerWithUnsignedExponent(double base,unsigned int exponent){
        double result = 1.0;
        for(int i=1;i<=exponent;++i)
            result*=base;
        
        return result;
    }
};