cata

cata.fsx

// Grenzen?
let toRoman arabic =

    let repeatChar char num =
        List.init num id
        |> List.fold (fun curr _ -> sprintf "%s%s" char curr) ""

    let zehnerUndHöher = arabic / 10
    let einer = arabic % 10
    let fünfer = einer / 5
    let einer = einer % 5

    let einerChars = repeatChar "I" einer
    let fünferChar = repeatChar "V" fünfer
    let zehnerUndHöherChars = repeatChar "X" zehnerUndHöher

    zehnerUndHöherChars + fünferChar + einerChars


let examples = [
    1, "I"
    2, "II"
    3, "III"
    4, "IIII"
    5, "V"
    6, "VI"
    7, "VII"
    8, "VIII"
    9, "VIIII"
    10, "X"
    11, "XI"
    12, "XII"
    13, "XIII"
    14, "XIIII"
    15, "XV"
    16, "XVI"
    17, "XVII"
    18, "XVIII"
    19, "XVIIII"
    20, "XX"
    21, "XXI"
    22, "XXII"
    23, "XXIII"
    24, "XXIIII"
    25, "XXV"
]

let actual = [1..25] |> List.map (fun x -> x, toRoman x)

actual = examples        

cata2.fsx

// Grenzen?
let toRoman arabic =

    let ( ** ) char num =
        List.init num id
        |> List.fold (fun curr _ -> sprintf "%s%s" char curr) ""

    let zehnerUndHöher = arabic / 10
    let einer = arabic % 10
    let fünfer = einer / 5
    let einer = einer % 5

    "X" ** zehnerUndHöher + "V" ** fünfer + "I" ** einer


let examples = [
    1, "I"
    2, "II"
    3, "III"
    4, "IIII"
    5, "V"
    6, "VI"
    7, "VII"
    8, "VIII"
    9, "VIIII"
    10, "X"
    11, "XI"
    12, "XII"
    13, "XIII"
    14, "XIIII"
    15, "XV"
    16, "XVI"
    17, "XVII"
    18, "XVIII"
    19, "XVIIII"
    20, "XX"
    21, "XXI"
    22, "XXII"
    23, "XXIII"
    24, "XXIIII"
    25, "XXV"
]

let actual = [1..25] |> List.map (fun x -> x, toRoman x)

actual = examples