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.
题目很好理解，就是判断一个数是不是ugly number，即一个数的质数因子只有2,3,5，只要有其他的质数因子就不是丑陋数，那么就不断除以2,3,5这几个质数，如果还有剩下的（即结果不是1那么它肯定还有其他的质数因子）
class Solution { public: bool isUgly(int num) { if(num==1) { return true; } else if(num<1) { return false; } else { while(num%2==0) { num=num/2; } while(num%3==0) { num=num/3; } while(num%5==0) { num=num/5; } if(num==1) { return true; } else { return false; } } } };
原文：http://www.cnblogs.com/liuyifei/p/Ugly_Number.html