sub key {
    $kp= shift;
    $caesar= shift;
#version 2 - this doesn't work - because autoincrement $a++ gets off when the key already exists!
#     foreach  (split(//, $kp),'a'..'z') {
#         $p2C{( exists $p2C{$_} ? '#' : $_)} = chr(ord('A')+(($a++)+$caesar)%26);
#     }

#version 3 - this doesn't work - why?
    %p2C = map {( exists $p2C{$_} ? '#' : $_ )=> chr(ord('A')+(($a++)+$caesar)%26) } (split(//, $kp),'a'..'z');
    %C2p = map {$p2C{$_} => $_} (keys %p2C);
    $p2C{' '}=' ';
    $C2p{' '}=' ';
}    

sub printKeys {
    my $href = shift;
    print "\nCT: ";
    print(($_).' ') foreach (sort keys %{$href});
    print "\npt: ";
    print(($$href{$_}).' ') foreach (sort keys %{$href});
    print "\n";
}

key ('thequickbrownfoxjumpsoverthelazydogs',10);

printKeys(\%p2C);
printKeys(\%C2p);