Data commit

Task/Number-names/OCaml/number-names.ocaml

@@ -0,0 +1,57 @@
+let div_mod n d = (n / d, n mod d)
+let join = String.concat ", " ;;
+
+let rec nonzero = function
+  | _, 0 -> ""
+  | c, n -> c ^ (spell_integer n)
+
+and tens n =
+  [| ""; ""; "twenty"; "thirty"; "forty"; "fifty";
+             "sixty"; "seventy"; "eighty"; "ninety" |].(n)
+
+and small n =
+  [| "zero"; "one"; "two"; "three"; "four"; "five";
+     "six"; "seven"; "eight"; "nine"; "ten"; "eleven";
+     "twelve"; "thirteen"; "fourteen"; "fifteen";
+     "sixteen";"seventeen"; "eighteen"; "nineteen" |].(n)
+
+and bl = [| ""; ""; "m"; "b"; "tr"; "quadr"; "quint";
+                    "sext"; "sept"; "oct"; "non"; "dec" |]
+
+and big = function
+  | 0, n -> (spell_integer n)
+  | 1, n -> (spell_integer n) ^ " thousand"
+  | e, n -> (spell_integer n) ^ " " ^ bl.(e) ^ "illion"
+
+and uff acc = function
+  | 0 -> List.rev acc
+  | n ->
+      let a, b = div_mod n 1000 in
+      uff (b::acc) a
+
+and spell_integer = function
+  | n when n < 0 -> invalid_arg "spell_integer: negative input"
+  | n when n < 20 -> small n
+  | n when n < 100 ->
+      let a, b = div_mod n 10 in
+      (tens a) ^ nonzero("-", b)
+  | n when n < 1000 ->
+      let a, b = div_mod n 100 in
+      (small a) ^ " hundred" ^ nonzero(" ", b)
+  | n ->
+      let seg = (uff [] n) in
+      let _, segn =
+        (* just add the index of the item in the list *)
+        List.fold_left
+          (fun (i,acc) v -> (succ i, (i,v)::acc))
+          (0,[])
+          seg
+      in
+      let fsegn =
+        (* remove right part "zero" *)
+        List.filter
+          (function (_,0) -> false | _ -> true)
+          segn
+      in
+      join(List.map big fsegn)
+;;