Pow(x, n)

 1 class Solution {
 2 public:
 3     double myPow(double x, int n) {
 4         if(!x) return 0.0;
 5         if(!n) return 1.0;
 6         if(n == 1) return x;
 7         
 8         if(n < 0) {
 9             double temp = myPow(1 / x, -(n / 2));
10             return temp * temp * myPow(1 / x, -(n % 2));
11         }
12         else{
13             double temp = myPow(x, n / 2);
14             return temp * temp * myPow(x, n % 2);
15         }
16     }
17 };