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。

public class Solution {
    public double Power(double base, int exponent) {
      boolean isFlag = false;
        if(exponent == 0)
            return 1;
        if(exponent == 1)
            return base;
        if(exponent<0)
        {
            exponent = -exponent;
            isFlag = true;
        }
        double total =1 ;
        int i = 1;
        for( ;  i <= exponent ; i++){
            total = total * base;
        }
        if(isFlag){
            return 1.0/total;
        }
        else {
            return total;
        }
  }
}