Ugly Number: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.

题意：把只包含因子2、3和5的数称作丑数。例如6、8都是丑数，但14不是丑数，因为它包含因子7。

思路：对于给定的整数n可以试着用2、3、5不断整除n。当n不能被2、3、5整除时，判断n的值是否等于1，等于1则返回True，否则返回False。

代码：

public boolean isUgly(int num) {          if(num==0) return false;          while(num%2==0) num/=2;          while(num%3==0) num/=3;          while(num%5==0) num/=5;          if(num==1){              return true;          }else{              return false;          }    }