Copy sub gray_encode ( Int $n - -> Int ) {
return $n +^ ( $n +> 1 );
}
sub gray_decode ( Int $n is copy - -> Int ) {
my $mask = 1 +< (32-2);
$n +^= $mask +> 1 if $n +& $mask while $mask +>= 1;
return $n;
}
for ^32 -> $n {
my $g = gray_encode($n);
my $d = gray_decode($g);
printf "%2d: %5b => %5b => %5b: %2d\n" , $n, $n, $g, $d, $d;
die if $d != $n;
}
Copy 0: 0 => 0 => 0: 0
1: 1 => 1 => 1: 1
2: 10 => 11 => 10: 2
3: 11 => 10 => 11: 3
4: 100 => 110 => 100: 4
5: 101 => 111 => 101: 5
6: 110 => 101 => 110: 6
7: 111 => 100 => 111: 7
8: 1000 => 1100 => 1000: 8
9: 1001 => 1101 => 1001: 9
10: 1010 => 1111 => 1010: 10
11: 1011 => 1110 => 1011: 11
12: 1100 => 1010 => 1100: 12
13: 1101 => 1011 => 1101: 13
14: 1110 => 1001 => 1110: 14
15: 1111 => 1000 => 1111: 15
16: 10000 => 11000 => 10000: 16
17: 10001 => 11001 => 10001: 17
18: 10010 => 11011 => 10010: 18
19: 10011 => 11010 => 10011: 19
20: 10100 => 11110 => 10100: 20
21: 10101 => 11111 => 10101: 21
22: 10110 => 11101 => 10110: 22
23: 10111 => 11100 => 10111: 23
24: 11000 => 10100 => 11000: 24
25: 11001 => 10101 => 11001: 25
26: 11010 => 10111 => 11010: 26
27: 11011 => 10110 => 11011: 27
28: 11100 => 10010 => 11100: 28
29: 11101 => 10011 => 11101: 29
30: 11110 => 10001 => 11110: 30
31: 11111 => 10000 => 11111: 31