Gray code: Difference between revisions

=={{header|Picat}}==

<lang Picat>go =>

foreach(I in 0..2**5-1)

G = gray_encode1(I),

E = gray_decode1(G),

printf("%2d %6w %2d %6w %6w %2d\n",I,I.to_binary_string,

G, G.to_binary_string,

E.to_binary_string, E)

end,

nl,

println("Checking 2**1300:"),

N2=2**1300,

G2=gray_encode1(N2),

E2=gray_decode1(G2),

% println(g2=G2),

% println(e2=E2),

println(check=cond(N2==E2,same,not_same)),

nl.

gray_encode1(N) = N ^ (N >> 1).

gray_decode1(N) = P =>

P = N,

N := N >> 1,

while (N != 0)

P := P ^ N,

N := N >> 1

end. </lang>

Output:

<pre> 0 0 0 0 0 0

1 1 1 1 1 1

2 10 3 11 10 2

3 11 2 10 11 3

4 100 6 110 100 4

5 101 7 111 101 5

6 110 5 101 110 6

7 111 4 100 111 7

8 1000 12 1100 1000 8

9 1001 13 1101 1001 9

10 1010 15 1111 1010 10

11 1011 14 1110 1011 11

12 1100 10 1010 1100 12

13 1101 11 1011 1101 13

14 1110 9 1001 1110 14

15 1111 8 1000 1111 15

16 10000 24 11000 10000 16

17 10001 25 11001 10001 17

18 10010 27 11011 10010 18

19 10011 26 11010 10011 19

20 10100 30 11110 10100 20

21 10101 31 11111 10101 21

22 10110 29 11101 10110 22

23 10111 28 11100 10111 23

24 11000 20 10100 11000 24

25 11001 21 10101 11001 25

26 11010 23 10111 11010 26

27 11011 22 10110 11011 27

28 11100 18 10010 11100 28

29 11101 19 10011 11101 29

30 11110 17 10001 11110 30

31 11111 16 10000 11111 31

Checking 2**1300

check = same</pre>