# 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.

The original problem is here.

The original code is here.

# My Solution

I solve this problem in C++, as below:

``````/*
*Ugly Number
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<stdlib.h>
using namespace std;

class Solution {
public:
bool isUgly(int num) {
if(num == 0)
return false;
if(num == 1)
return true;
if(num % 2 == 0){
if(num/2 == 0)
return true;
return isUgly(num/2);
}

else if(num % 3 == 0){
if(num/3 == 0)
return true;
return isUgly(num/3);
}
else if(num % 5 == 0){
if(num/5 == 0)
return true;
return isUgly(num/5);
}
else
return false;
}
};

int main(){
Solution s;
int num = 14;
bool result = s.isUgly(num);
cout<<"Result="<<result<<endl;
system("pause");
return 0;
}
``````

# Note

Recursion is used to the problem.