sub highest_number{
use strict;
use File::Basename;
use Cwd;

my ($aref, $filetype, $word) = @_;
my $number;
my @matching;
my $ext = ".".$filetype;
push (@matching, 0); #min returned value
for my $file (@{$aref}) {
#print "file is $file\n";
if ($file =~ /^$word(\d*)$ext$/){
   #print "matching is $file\n";
   push (@matching, $1);
   }
}
@matching = sort @matching;
my $winner  = pop @matching;
return $winner  
}