my %messages = (
  -1 => "too low",
   0 => "just right",
   1 => "too high",
);

while (...) {
  print $messages{ $guess <=> $answer }, "\n";
}

##</code><code>##

my @messages = (
  "just right",
  "too high",
  "too low",
);

print $messages[$guess <=> $answer];