use Text::CSV_XS;

my $csv = Text::CSV_XS->new ({ binary => 1, eol => "\r\n", auto_diag => 1 });

##</code><code>##

$csv->print (OUT, \@heading);

##</code><code>##

$csv->print (OUT, [ $_ ]) for @arr;

##</code><code>##

while (my $row = <IN>) {
    push @arr, [ unpack "x0 A12 ..." => $row ];
    }
# @arr now holds a list of array refs
$csv->print (OUT, $_) for @arr;