One-dimensional cellular automata: Difference between revisions

=={{header|Retro}}==

<lang Retro>: $, dup getLength 0 swap for 2dup + @ , 1+ next 2drop 0 , ;

create world ".###.##.#.#.#.#..#.." $,

create world2 21 allot

create group 4 allot

variable neighbors

: middle ( - )

0 !neighbors

group @ '# =if neighbors ++ then

group 2 + @ '# =if neighbors ++ then

;

: left.edge ( - ) @world '# =if 1 else 0 then !neighbors ;

: right.edge ( - ) world 19 + @ '# =if 1 else 0 then !neighbors ;

: flip ( n-n ) dup world + @ '# =if '. ;then '# ;

: check ( n-n )

dup 0 =if left.edge ;then

dup 19 =if right.edge ;then

dup world + 1- group 3 copy middle ;

: gen ( - )

0 20 for

0 !neighbors

check

@neighbors 0 =if dup world2 + '. swap ! then

@neighbors 1 =if dup world + @ over world2 + ! then

@neighbors 2 =if flip over world2 + ! then

1+

next drop

world2 world 20 copy ;

: generations ( n- )

clear 0 swap for dup putn space world puts cr gen 1+ next drop ;</lang>

Sample Output:

<pre>10 generations

0 .###.##.#.#.#.#..#..

1 .#.#####.#.#.#......

2 ..##...##.#.#.......

3 ..##...###.#........

4 ..##...#.##.........

5 ..##....###.........

6 ..##....#.#.........

7 ..##.....#..........

8 ..##................

9 ..##................</pre>