LeetCode : Power of Four

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example:
Given num = 16, return true. Given num = 5, return false.

Follow up: Could you solve it without loops/recursion?

class Solution {
public:
    bool isPowerOfFour(int num) {
       while(num&&(num%4==0))
       {
           num/=4;
       }
       if(num==1)
           return true;
       else
           return false;
    }
};