阿里笔试题——算阶乘的末尾有几个零

#include<iostream>
using namespace std;
#define LINT int
LINT count_number(LINT n)
{
LINT a=n;
LINT re=0;
while(1)
{
if(a==0)
break;
LINT b=a;
a--;
while((b!=0)&&(b%3==0))
{
re++;
b=b/3;
}
}
return re;
}
int main()
{
cout<<count_number(30)<<endl;

}