====== - 利用POSIX模块处理 向下/向上取整 ======


 
<code perl>
use POSIX;

POSIX::ceil(3.14) => 4   #向上取整

POSIX::floor(3.14) => 3   # 向下取整， 等同于 int(3.14)

</code> 

====== - 利用Math::Round 做四舍五入 ======

 
<code perl>
use Math::Round;

my $num = 45.4;

my $round = Math::Round($num);
</code>