We can use quick power to slove this problem

This is my source code that used quick power

```
class Solution {
public:
//quick power
double pow(double x, int n)
{
if(n == 0) return 1;
if(n == 1) return x;
double result = pow(x, n / 2);
result *= result;
if(n & 1) result *= x;
return result;
}
double myPow(double x, int n) {
x = pow(x, n < 0 ? -1 * n : n); //get the number pow(x, |n|)
if(n < 0) x = 1 / x; //if n i a negative number
return x; //return result
}
};
```

But I find that we can direct call the pow function in C++

for example

```
class Solution {
public:
double myPow(double x, int n) {
return pow(x,n);
}
};
```