Ugly Number--leetcode

Write a program to check whether a given number is an ugly number.

Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.

Note that 1 is typically treated as an ugly number.
判断一个数的因子是不是只有2或者3或者5。使用递归的思想。

c++:

class Solution {
public:
    bool isUgly(int num) {
        if (num == 1) return true;
        if (num == 0) return false;

        else if (num % 2 == 0) return isUgly(num / 2);
        else if (num % 3 == 0) return isUgly(num / 3);
        else if (num % 5 == 0) return isUgly(num / 5);

        else return false; 

    }
};