Listen, Tupel und Records

let () =
  let z = [5; 3; 9; 1; 7] in
  let zeige l = print_endline ("[" ^ String.concat "; " (List.map string_of_int l) ^ "]") in
  zeige z;
  zeige (0 :: z);
  zeige (z @ [8; 9]);
  zeige (List.rev z);
  zeige (List.sort compare z);
  zeige (List.map (fun x -> x * 2) z);
  zeige (List.filter (fun x -> x > 4) z);
  Printf.printf "%d %d\n" (List.length z) (List.hd z);
  Printf.printf "%d\n" (List.fold_left (+) 0 z);
  Printf.printf "%b %b\n" (List.mem 9 z) (List.exists (fun x -> x > 8) z);
  Printf.printf "%b\n" (List.for_all (fun x -> x > 0) z);
  zeige (List.init 5 (fun i -> i * i));
  zeige (List.concat [[1; 2]; [3]; [4; 5]]);
  List.iteri (fun i x -> Printf.printf "%d:%d " i x) [10; 20; 30];
  print_newline ();
  let (gerade, ungerade) = List.partition (fun x -> x mod 2 = 0) [1; 2; 3; 4; 5; 6] in
  zeige gerade; zeige ungerade;
  let paare = List.combine [1; 2; 3] ["a"; "b"; "c"] in
  List.iter (fun (n, s) -> Printf.printf "%d%s " n s) paare;
  print_newline ()

let rec summe = function
  | [] -> 0
  | kopf :: rest -> kopf + summe rest

let rec laenge = function
  | [] -> 0
  | _ :: rest -> 1 + laenge rest

let rec map f = function
  | [] -> []
  | x :: rest -> f x :: map f rest

let rec nimm n l = match n, l with
  | 0, _ | _, [] -> []
  | n, x :: rest -> x :: nimm (n - 1) rest

let () =
  Printf.printf "%d %d\n" (summe [1; 2; 3; 4]) (laenge ["a"; "b"; "c"]);
  List.iter (Printf.printf "%d ") (map (fun x -> x * x) [1; 2; 3; 4]);
  print_newline ();
  List.iter (Printf.printf "%d ") (nimm 2 [10; 20; 30]);
  print_newline ()

let min_max l =
  List.fold_left (fun (lo, hi) x -> (min lo x, max hi x)) (max_int, min_int) l

let () =
  let punkt = (3, 4) in
  let (x, y) = punkt in
  Printf.printf "%d %d %d %d\n" x y (fst punkt) (snd punkt);
  let (lo, hi) = min_max [5; 2; 9; 4] in
  Printf.printf "%d %d\n" lo hi;
  let dreifach = ("Mia", 17, true) in
  let (n, a, _) = dreifach in
  Printf.printf "%s %d\n" n a

type person = { name : string; alter : int; mutable punkte : int }

let () =
  let p = { name = "Mia"; alter = 17; punkte = 0 } in
  Printf.printf "%s %d\n" p.name p.alter;
  p.punkte <- p.punkte + 10;
  Printf.printf "%d\n" p.punkte;
  (* unveränderliche Kopie mit Änderung *)
  let q = { p with alter = 18 } in
  Printf.printf "%s %d %d\n" q.name q.alter q.punkte;
  let { name; alter; _ } = q in
  Printf.printf "%s ist %d\n" name alter

let teile a b = if b = 0 then None else Some (a / b)

let () =
  (match teile 10 2 with
   | Some r -> Printf.printf "Ergebnis %d\n" r
   | None -> print_endline "Division durch null");
  (match teile 1 0 with
   | Some r -> Printf.printf "Ergebnis %d\n" r
   | None -> print_endline "Division durch null");
  Printf.printf "%d\n" (Option.value (teile 8 4) ~default:(-1));
  Printf.printf "%d\n" (Option.value (teile 8 0) ~default:(-1));
  (match Option.map (fun x -> x + 1) (Some 4) with Some v -> Printf.printf "%d\n" v | None -> ());
  (match List.find_opt (fun x -> x > 3) [1; 5; 9] with Some v -> Printf.printf "%d\n" v | None -> ())