#!/usr/bin/perl

use strict;
use warnings;

my @words;
my $word;
my $text;
my $file = "test.txt";
open (DATA, "+<", $file)
    or die("Could not open file: ".$file.". $!\n");

sub add {
    print "I am in\n";
    while( <DATA> ) {	
	chomp;
	@words = split('');
	foreach $word (@words) {
	    print "This is word: ".$word."\n";
	    $text = $word + 1;
	    print "This is the new word: ".$text."\n";
	}
    }
}

&add();
print DATA "".$text."\n";
close (DATA);