确定N!末尾有几个0

确定N!末尾有几个0

其实就是找1到n有多少个因子5

int fun2(int n)
{
	int num = 0;
	int i, j;
 
	for (i = 5; i <= n; i += 5)
	{
		j = i;
		while (j % 5 == 0)
		{
			num++;
			j /= 5;
		}
	}
	return num;
}