Leetcode:Pow(x,n)

 1 class Solution {
 2 public:
 3     double findval(double x,int n)
 4     {
 5         if(n==0) return 1;
 6         if(n==1) return x;
 7         double value = pow(x,n/2);
 8         if(n%2) return value*value*x;
 9         else return value*value;
10     }
11     double pow(double x, int n) {
12         bool flag = false;
13         if(n<0)
14         {
15             n=-n;
16             flag = true;
17         }
18         double value = findval(x,n);
19         if(flag) return 1/value;
20         else return value;
21         
22     }
23 };