sub binary {
  my ($n) = @_;
  return $n if $n == 0 || $n == 1; 
  my $k = int($n/2);
  my $b = $n % 2;
  print "n is $n.\nk is $k.\nb is $b.\n";
  print "above\n";
  my $E = binary($k);
  print "below\n";
  print "n is $n.\nE is $E.\n\n";
  return $E . $b;
}

print binary(8);

##</code><code>##

n is 8.
k is 4.
b is 0.
above
n is 4.
k is 2.
b is 0.
above
n is 2.
k is 1.
b is 0.
above
below
n is 2.
E is 1.

below
n is 4.
E is 10.

below
n is 8.
E is 100.

1000