#!/usr/bin/perl
#t_concat

my $file = $ARGV[0];
local ($/) = undef;
open FH, $file or die;
my $data = <FH>;
close FH;

my $len = length($data);
my $result;
my $c;

for($i = 0; $i < $len; $i++){
    $c = substr $data, $i, 1;
    #concatenate onto result.
    $result .= $c;
}

print $result;

##</code><code>##

#!/usr/bin/perl
#t_join
$file = $ARGV[0];
local ($/) = undef;
open FH, $file or die;
my $data = <FH>;
close FH;

my $len = length($data);
my @result;
$#result = $len;
my $c;

for($i = 0; $i < $len; $i++){
    $c = substr $data, $i, 1;
    #put the string in an array for later join.
    $result[$i] = $c;
}

print join('', @result);