public static string recur$($int val$)$

$\{$

if $)==(0$

$\{$

return $""$;

$\}$

if $($val $2==0)$

$\{$

return recur$($val $/2)+"$f$"$;

recur$(13)=$

$\}$

else

$\{$

return recur$($val $/2)+"$t$"$;

$\}$

$\}$