$hash{a} = 0;
$hash{b} = 1;
$hash{c} = 0;
$hash{d} = 3;

##</code><code>##

a = 0
c = 0
b = 1
d = 3

##</code><code>##

c = 0
a = 0
b = 1
d = 3

##</code><code>##

foreach my $k ( sort { $hash{$a} <=> $hash{$b}  } keys %hash  ) {
    print "$k = $hash{$k}\n";
}