levels = {[[
0000000000
0........0
0........0
0........0
0........0
0........0
0........0
0s.......0
0........0
0000000000
]]
}

to_write = ""

--remove all "\n" from level strings
for i, v in ipairs(levels) do
  v = string.gsub(v, "\n", "")
  to_write = to_write.."    case "..(i-1)..":\n      level = \""..v.."\";\n    break;"
end

--finish and write
to_write = [[#include "levels.h"
void get_level(unsigned char level_id, char level[]) {
  switch (level_id)
  {
]]..to_write.."\n  }\n}\n"
io.write(to_write)