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.
Do it recursively.
bool isUgly(int num) { if(num < 1) return false; if(num == 1) return true; 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; }