Aufgabe 01 in 3 Ausführungen

aufgabe-01/src/Aufgabe_01.elm

@@ -0,0 +1,31 @@
+module Aufgabe_01 exposing (..)
+
+import Html exposing (text, ul, li)
+import List exposing (map)
+
+euro : List Int
+euro = [50000, 20000, 10000, 5000, 2000, 1000, 500, 200, 100, 50, 20, 10, 2, 1]
+
+input : Int
+input = 4711
+
+
+change : Int -> List Int -> Result String (List Int)
+change amount currency =
+    if amount == 0 then Ok []
+
+    else
+        case currency of
+            head :: tail ->
+                if head < amount then
+                    case change (amount - head) currency of
+                        Err message -> Err message
+                        Ok rest -> Ok (head :: rest)
+
+                else change amount tail
+            [] -> Err "Kein Wechselgeld"
+
+
+main = case change input euro of
+            Ok changed -> ul [] (map (\x -> li [] [(text (String.fromInt x))]) changed)
+            Err message -> text message

aufgabe-01/src/Aufgabe_01_2.elm

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+module Aufgabe_01_2 exposing (..)
+
+import Html
+
+euro : List Int
+euro = [50000, 20000, 10000, 5000, 2000, 1000, 500, 200, 100, 50, 20, 10, 2, 1]
+
+
+wechseln : Int -> List Int -> Result String (List Int)
+wechseln geldMenge waehrung =
+    if geldMenge <= 0 then Ok []
+    else case waehrung of
+             head :: tail -> if head <= geldMenge
+                        then case wechseln (geldMenge - head) waehrung of
+                                 Err msg -> Err msg
+                                 Ok wechselgeld -> Ok (head :: wechselgeld)
+                        else wechseln geldMenge tail
+             [] -> Err "Kein Wechselgeld"
+
+
+result = wechseln 4711 euro
+
+main = case result of
+           Ok wechselgeld -> Html.ul [] (List.map (\x -> Html.li [] [Html.text (String.fromInt x)]) wechselgeld)
+           Err msg -> Html.text msg
+

aufgabe-01/src/Aufgabe_01_3.elm

@@ -0,0 +1,25 @@
+module Aufgabe_01_3 exposing (..)
+
+import Html
+
+euro : List Int
+euro = [50000, 20000, 10000, 5000, 2000, 1000, 500, 200, 100, 50, 20, 10, 2, 1]
+
+change : Int -> List Int -> Result String (List Int)
+change amount currency =
+    if amount <= 0
+    then Ok []
+    else case currency of
+             [] -> Err "No change available"
+             head :: tail ->
+                 if head <= amount
+                 then case change (amount - head) currency of
+                          Ok c -> Ok (head :: c)
+                          Err msg -> Err msg
+                 else change amount tail
+
+
+result = change 7563 euro
+main = case result of
+           Err msg -> Html.text msg
+           Ok money -> Html.ul [] (List.map (\x -> Html.li [] [Html.text (String.fromInt x)]) money)

aufgabe-01/src/Aufgabe_01_musterloesung.elm

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+module Aufgabe_01 exposing (..)
+
+import Html exposing (text, ul, li)
+import List exposing (map)
+
+
+
+type alias Amount =
+    Int
+
+
+type alias Money =
+    List Int
+
+
+input : Amount
+input =
+    4711
+
+
+euro : Money
+euro =
+    [ 50000
+    , 20000
+    , 10000
+    , 5000
+    , 2000
+    , 1000
+    , 500
+    , 200
+    , 100
+    , 50
+    , 20
+    , 10
+    , 2
+    , 1
+    ]
+
+
+change : Amount -> Money -> Result String Money
+change amount currency =
+    if amount == 0 then
+        Ok []
+
+    else
+        case currency of
+            head :: tail ->
+                if head <= amount then
+                    case change (amount - head) currency of
+                        Err message ->
+                            Err message
+
+                        Ok rest ->
+                            Ok (head :: rest)
+
+                else
+                    change amount tail
+
+            [] ->
+                Err "kein Wechselgeld"
+
+
+main = case change input euro of
+            Ok changed ->
+                 ul [] (map (\x -> li [] [(text (String.fromInt x))]) changed)
+
+            Err message ->
+                text message

aufgabe-01/src/Main.elm

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+module Main exposing (main)
+
+import Browser
+import Html exposing (Html, button, div, text)
+import Html.Events exposing (onClick)
+
+
+-- MAIN
+main = Browser.sandbox { init = init, update = update, view = view }
+
+
+
+-- MODEL
+type alias Model = Int
+
+init : Model
+init =
+  0
+
+
+-- UPDATE
+type Msg = Increment | Decrement
+
+update : Msg -> Model -> Model
+update msg model =
+  case msg of
+    Increment ->
+      model + 1
+
+    Decrement ->
+      model - 1
+
+
+-- VIEW
+view : Model -> Html Msg
+view model =
+  div []
+    [ button [ onClick Decrement ] [ text "-" ]
+    , div [] [ text (String.fromInt model) ]
+    , button [ onClick Increment ] [ text "+" ]
+    ]