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.
solution: according to defination, only be divided by 2,3,5
public boolean isUgly(int num) {
if(num<=0) return false;
while(num%2 == 0){
num = num/2;
}
while(num%3 == 0){
num = num/3;
}
while(num%5 == 0){
num = num/5;
}
return num == 1;
}