use strict;
my $operator=<STDIN>;
my $op_map={};
my $one=10;
my $two=5;
chomp $operator;
define_op_map();
if ( defined ($op_map->{$operator}) ) {
  &{$op_map->{$operator}};
  } else {
  print "This op is undefined. Executing it might end the universe as we know it.\n";
  }

sub define_op_map {
  $op_map->{'+'}=sub{print $one + $two . "\n"};
  $op_map->{'-'}=sub{print $one - $two . "\n"};
  $op_map->{'*'}=sub{print $one * $two . "\n"};
  $op_map->{'/'}=sub{print $one / $two . "\n"};
  }

##</code><code>##

$op_map->{'camel'}=sub{print "$one is a $two with humps.\n"};