foreach $c (each %couples) {
   print "$c\n";
};

##</code><code>##

foreach $c ("abbot","costello") {
   print "$c\n";
};

##</code><code>##

while (my ($c,$d) = each %couples){
  print "$c $d\n";
}

##</code><code>##

print "$_ $couples{$_}$/" for (keys %couples);