Ugly Number

 

Description：

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.

Code：

 bool isUgly(int num)
    {
        if (num < 1)
            return false;
        if (num == 1)
            return true;
        else
        {
            int result1=false, result2=false, result3=false;
            if (num%2==0)
                result1 = isUgly(num/2);
            if (num%3 == 0)
                result2 = isUgly(num/3);
            if (num%5==0)
                result3= isUgly(num/5);
            return result1 || result2 || result3;
        }
    }