Just for kicks, here's my corrolary, where the computer guesses. It turned out a lot simpler. I'm trying harder to make it pretty, too.

#The computer will try to guess your number.
#Watch out!  It knows if you're cheating.

use strict;
use warnings;

sub game{
  my $min=0;
  my $max=200;
  my $guess;
  my $response="h";

  print "Think of a number between $min and $max, and I will guess wha
+t it is.  Type h if your number is higher than my guess, and type l i
+f it is lower. Type = if I have guessed your number.\n";

  while ($response ne "="){
    if ((($max-$min)/2)<1){    
      print "You're not playing fair!  I quit.\n";
      return;    
    }
    else{
      $guess=int($max-(($max-$min)/2));
      print "My guess is ",$guess,".\n";
      $response = <STDIN>;
      chomp($response);
      if ($response eq "h"){
        $min=$guess;
      }
      elsif ($response eq "l"){
        $max=$guess;
      }
    }
  }
}

my $again = 'y';
while ($again eq 'y'){
    game();
    print "That was fun--no really, it was.  Play again? (y/n) \n";

    $again = <STDIN>;
    chomp ($again);
}
print "Goodbye!\n";
[download]