link printf

procedure main()
   every put(environment := [], hailenv(1 to 12,0))  # setup environments
   printf("Sequences:\n")
   while (e := !environment).sequence > 1 do {
      every hailstep(!environment)
      printf("\n")
      }
   printf("\nCounts:\n")
   every printf("%4d ",(!environment).count)
   printf("\n")
end

record hailenv(sequence,count)

procedure hailstep(env)
   printf("%4d ",env.sequence)
    if env.sequence ~= 1 then {
        env.count +:= 1
        if env.sequence % 2 = 0 then env.sequence /:= 2
        else env.sequence := 3 * env.sequence + 1
        }
end