Round with precision to 5 Swiss Rp.

Meta Code

#!/usr/bin/perl -w

my $amount = $ARGV[0];
require "rounder_include.pl";
print &round_amount($amount), "\n";

Samples

# perl test.pl
 33.32   is rounded      33.30
 33.99   is rounded      34.00
 33.38   is rounded      33.40
 33.33   is rounded      33.35
 99.99   is rounded     100.00
110.58   is rounded     110.60
 19.03   is rounded      19.05

Implementation

I know there is a better solution but it's late in the nite and this work well ;-)

my @tests = qw(33.32 33.99 33.38 33.33 99.99 110.58 19.03);

print "$_\t is rounded\t", &round_amount($_), "\n" foreach @tests;


sub round_amount ($) {

        my $amount = $_[0];

        my $frac   = sprintf("%.2f", $amount - int($amount));
        my $ten    = substr(sprintf("%02d", ($frac * 100)), 0, 1);
        my $decmak = substr(sprintf("%02d", ($frac * 100)), 1, 1);

        my $result = my $rounded = 0;

        if (!($decmak % 5) or !$decmak) {
                # nothing to round
                $rounded = sprintf("%.2f", $amount);
        }
        else {
                $result = ($decmak == 1 or $decmak == 2 or $decmak == 8 or $decmak == 9) ? 0 : 5;

                $rounded = int($amount) . '.' . $ten . $result;
                $rounded += .1 if $decmak > 7;
                $rounded = sprintf("%.2f", $rounded);
        }

        $rounded;
}