I realise this is more than an algorithmic question, but figured someone here has a higher level of math geekyness than i.

What i want to do is round an integer to the closest unit.

In this specific case, i'm running a cronjob every five mins, and putting the data into a database for later processing.

What i'm after is rounding the timestamp from the database to the nearest 5 mins. I've come up with something, which seems to work, however i'm wondering if this is the most efficient way to do it.

#!/usr/bin/perl -w

use strict;

my @time = localtime(time);

my $prec   = 5;
my $number = 52;

$\="\n";

my $div = $number%$prec;
$div = 1 if ($div == 0);

my $num = sprintf("%.1f", $number/$div );
my $intnum = int sprintf("%.1f", $number/$div );

if ( ($num-$intnum) >= .5) {
    print $prec-($number%$prec)+$number;
} else {
    print $number-($number%$prec);
}
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