(* Problem 5 *)
(* numberToName (a)
TYPE: int -> string
PRE: int 0-99
POST: ett heltal representerat av dess bokstaverade motsvarighet
EXAMPLES: numberToName(1) -> "ett"
EXAMPLES: numberToName(40) -> "fyrtio"
*)
fun numberToName (a):string =
  case a of
    0 => "noll"
  | 1 => "ett"
  | 2 => "två"
  | 3 => "tre"
  | 4 => "fyra"
  | 5 => "fem"
  | 6 => "sex"
  | 7 => "sju"
  | 8 => "åtta"
  | 9 => "nio"
  | 10 => "tio"
  | 11 => "elva"
  | 12 => "tolv"
  | 13 => "tretton"
  | 14 => "fjorton"
  | 15 => "femton"
  | 16 => "sexton"
  | 17 => "sjutton"
  | 18 => "artton"
  | 19 => "nitton"

  | 20 => "tjugo"
  | 30 => "trettio"
  | 40 => "fyrtio"
  | 80 => "åttio"
  | 90 => "nittio"

  | x => if x > 20 andalso x < 100 then
case ord(createchar(Int.toString(x)))*10 of
    10 => "tio"
  | 11 => "elva"
  | 12 => "tolv"
  | 13 => "tretton"
  | 14 => "fjorton"
  | 15 => "femton"
  | 16 => "sexton"
  | 17 => "sjutton"
  | 18 => "artton"
  | 19 => "nitton"

  | 20 => "tjugo"
  | 30 => "trettio"
  | 40 => "fyrtio"
  | 80 => "åttio"
  | 90 => "nittio"
else
"noll";


(50, numberToName(1) = "ett");
(51, numberToName(40) = "fyrtio");