From 363950478d6559fe312be1762782efd67972354c Mon Sep 17 00:00:00 2001
From: Arkitu <git@arkitu.fr>
Date: Tue, 9 Dec 2025 17:35:18 +0100
Subject: [PATCH] td4

---
 td4/td4.ml | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 td4/td4.ml

diff --git a/td4/td4.ml b/td4/td4.ml
new file mode 100644
index 0000000..fe68d2b
--- /dev/null
+++ b/td4/td4.ml
@@ -0,0 +1,97 @@
+(* Exercice 1 *)
+let rec rev_h l acc = match l with
+  | [] -> acc
+  | a::q -> rev_h q (a::acc)
+;;
+let rec rev l = rev_h l [];;
+
+let rec for_all f l = match l with
+  | [] -> true
+  | a::q -> f a && for_all f q
+;;
+
+let rec exists f l = match l with
+  | [] -> false
+  | a::q -> f a || exists f q
+;;
+
+let rec mem x l = match l with
+  | [] -> false
+  | a::q -> a=x || mem x q
+;;
+
+(* Exercice 2 *)
+let rec map f l = match l with
+  | [] -> []
+  | a::q -> f a::map f q
+;;
+
+let rec iter f l = match l with
+  | [] -> ()
+  | a::q -> let () = f a in iter f q
+;;
+
+let rec filter f l = match l with
+  | [] -> []
+  | a::q ->
+    if f a then
+      a::filter f q
+    else
+      filter f q
+;;
+
+let rec fold_right f l acc = match l with
+  | [] -> acc
+  | a::q -> f a (fold_right f q acc)
+;;
+
+let rec fold_left f acc l = match l with
+  | [] -> acc
+  | a::q -> fold_left f (f acc a) q
+;;
+
+(* Exercice 3 *)
+let rec print_list print l =
+  print_string "[";
+  List.iter (fun a -> print a; print_string ",") l;
+  print_string "]"
+;;
+
+(* Exercice 4 *)
+let for_all f l = List.fold_left (fun acc a -> acc && f a) true l;;
+
+let exists f l = List.fold_left (fun acc a -> acc || f a) false l;;
+
+let mem x l = exists (fun a -> a=x);;
+
+(* Exercice 5 *)
+let fact n =
+  let rec l n =
+    if n > 0 then
+      n::l (n-1)
+    else []
+  in
+  List.fold_left (fun acc a -> acc * a) 1 (l n)
+;;
+
+(* Exercice 6 *)
+let init n f = if n = 0 then [||] else
+  let res = Array.make n (f 0) in
+  for i = 1 to n do
+    res.(i) <- f i
+  done;
+  res
+;;
+
+let copy t = init (Array.length t) (fun i -> t.(i));;
+
+let mem x t =
+  let b = ref false in
+  let i = ref 0 in
+  let n = Array.length t in
+  while !i < n && (not !b) do
+    b := t.(!i) = x;
+    i := !i+1;
+  done;
+  !b
+;;