Implement pow(x, n), which calculates x raised to the power n.
Handle negative exponents and return the computed numeric result.
Examples
Input: x = 2.0, n = 10 Output: 1024.0
Input: x = 2.0, n = -2 Output: 0.25
Input: x = -2.0, n = 3 Output: -8.0
Constraints
- -100.0 < x < 100.0
- -2^31 <= n <= 2^31 - 1
- Either x is not zero or n > 0.