$ include "seed7_05.s7i";
  include "bin32.s7i";

const func integer: grayEncode (in integer: n) is
  return ord(bin32(n) >< bin32(n >> 1));

const func integer: grayDecode (in var integer: n) is func
  result
    var integer: decoded is 0;
  begin
    decoded := n;
    while n > 1 do
      n >>:= 1;
      decoded := ord(bin32(decoded) >< bin32(n));
    end while;
  end func;

const proc: main is func
  local
    var integer: i is 0;
  begin
    for i range 0 to 32 do
      writeln(i <& " => " <& grayEncode(i) radix 2 lpad0 6 <& " => " <& grayDecode(grayEncode(i)));
    end for;
  end func;