Data commit

Task/Roman-numerals-Encode/F-Sharp/roman-numerals-encode.fs

@@ -0,0 +1,28 @@
+let digit x y z = function
+    1 -> x
+  | 2 -> x + x
+  | 3 -> x + x + x
+  | 4 -> x + y
+  | 5 -> y
+  | 6 -> y + x
+  | 7 -> y + x + x
+  | 8 -> y + x + x + x
+  | 9 -> x + z
+  | _ -> failwith "invalid call to digit"
+
+let rec to_roman acc = function
+    | x when x >= 1000 -> to_roman (acc + "M") (x - 1000)
+    | x when x >= 100 -> to_roman (acc + digit "C" "D" "M" (x / 100)) (x % 100)
+    | x when x >= 10 -> to_roman (acc + digit "X" "L" "C" (x / 10)) (x % 10)
+    | x when x > 0 -> acc + digit "I" "V" "X" x
+    | 0 -> acc
+    | _ -> failwith "invalid call to_roman (negative input)"
+
+let roman n = to_roman "" n
+
+[<EntryPoint>]
+let main args =
+    [1990; 2008; 1666]
+    |> List.map (fun n -> roman n)
+    |> List.iter (printfn "%s")
+    0