foreach my $i (0 .. @titles) {
  print "Title: $title[$i]\n";
  print "Author: $author[$i]\n";
  print "Date: $date[$i]\n\n";
}

##</code><code>##

Use of uninitialized value within @titles in concatenation (.) or string at bdb.pl line 51.
Title: 
Use of uninitialized value within @authors in concatenation (.) or string at bdb.pl line 52.
Author: 
Use of uninitialized value within @date in concatenation (.) or string at bdb.pl line 53.
Date: