Elementary cellular automaton: Difference between revisions

</pre>

=={{header|UNIX Shell}}==

{{trans|Common Lisp}}

{{works with|Bourne Again SHell}}

{{works with|Korn Shell}}

<lang bash>function print_cells {

local chars=(. '#') cell

for cell; do

printf '%s' "${chars[$cell]}"

done

printf '\n'

}

function next_gen {

local rule=$1

shift

cells=("$@")

local -i l c r bit

for (( l=$#-1, c=0, r=1; c < $#;

l=(l+1)%$#, c+=1, r=(r+1)%$# )); do

local left=${cells[l]} current=${cells[c]} right=${cells[r]}

(( bit = 1<<(left<<2 | current<<1 | right) ))

printf '%d\n' $(( rule & bit ? 1 : 0 ))

done

}

function automaton {

local size=${1:-32} rule=${2:-90} stop=${3:-$(( size/2 ))}

local i gen cells=()

for (( i=0; i<size; ++i )); do

cells+=( $(( i == size/2 )) )

done

for (( gen=0; gen<stop; ++gen )); do

printf "%${#stop}d: " "$gen"

print_cells "${cells[@]}"

cells=($(next_gen "$rule" "${cells[@]}"))

done

}

automaton "$@"

</lang>

{{Out}}

<pre> 0: ................#...............

1: ...............#.#..............

2: ..............#...#.............

3: .............#.#.#.#............

4: ............#.......#...........

5: ...........#.#.....#.#..........

6: ..........#...#...#...#.........

7: .........#.#.#.#.#.#.#.#........

8: ........#...............#.......

9: .......#.#.............#.#......

10: ......#...#...........#...#.....

11: .....#.#.#.#.........#.#.#.#....

12: ....#.......#.......#.......#...

13: ...#.#.....#.#.....#.#.....#.#..

14: ..#...#...#...#...#...#...#...#.

15: .#.#.#.#.#.#.#.#.#.#.#.#.#.#.#.#