剑指offer：数值的整数幂次

class Solution {
public:
    double Power(double base, int exponent) {
        bool posit = (exponent > 0) ? true : false;
        exponent = posit ? exponent : (-exponent);
        if(!exponent){
            return 1;
        }
        double tmp = base;
        for(int i=1;i<exponent;++i){
            tmp *= base;
        }
        if(posit){
            return tmp;
        }
        else{
            return 1/tmp;
        }
    }
};