1+2;;              
"Hello" ^ "world";;
let x = 2+3;;      
x+x;;
let f  x =  2*x + 3;;
 f 4;;
let g x = f ( f x);;
2 + 3 * 4;;
13.4e-3 ;;
sqrt(56.3);;
2<3;;
  2.5>3.6;;
   1 > 5.5;;
  not false && false ;;
  not (false && false);;
  true || false;;
   8638 mod 7 =0;;
 'a';; 
 '\'';;
 '\097';;               
 '\039';;
 int_of_char 'a';;          (* int_of_char : char -> int*)
 char_of_int (int_of_char 'a');; (* char_of_int : int -> char*)
"ceci est une chaîne de caractères";;
String.length ("ceci est une" ^ " chaîne");;
String.uppercase "ceci est une" ;;
let x = 1 ;;
let y = true;;
let b = true in b && (not b) ;;
not b;;
(let x = 4 + 1 in x*x) + 10;;
let a = 3;;                  
let a = 10 in a+1;;          
a;;                          
let r = if 1<2 then 1.34 else "bonjour" ;;
("il est passé") ^ (if 1<2 then " par ici" else " par là");;
("il est passé") ^ (if 1>2 then " par ici" else " par là");;
 function a -> a - 2;;      
let carré = function x -> x*x ;;
let carré x =  x * x ;;
let aire_cercle = 
  let pi = 3.14 in function r -> pi *. r *. r;;
let triple y = let car x = x * x in car (y)*y;;
let f x = let g y = x + y in (g 2) + x;;
 function (lo,la) -> lo*la;;
let aire_rect (lo,la) = lo*la;;
carré(25);;                       
carré 25;;                        
carré true;;  
carré (3+1);;                     
carré 3 + 4;;                     
aire_rect (3,4);;                  
let x = "ici";;
let f s = s  ^  x ;;
f "Que vois-je? " ;;
let x = "la bas";;
f "Que vois-je ?" ;;
let rec fact n = 
   if n = 0 then 1 else n * fact (n - 1) ;;
fact 10 ;;
 fact (-5);;
let somme n = 
   if n = 0 then 0 else n + somme (n - 1) ;;
let rec somme n = 
   if n = 0 then 0 else n + somme (n - 1) ;;
 somme 14;;
 let h x = if x = 1. then failwith "h : indefini" else 1. /. (x -. 1.);;
h 2.;;
h 1.;;
let predecesseur y =
  if y <= 0 
  then failwith "predecesseur : parametre non naturel" 
  else y - 1;;
predecesseur (-5);;
aire_cercle (h 1.);;
[1;2;3];;
[1;true];;
1::2::[];;
[ [true]; []; [true;false] ] ;;
 [1;2] @ [3];;
 let mettre_en_liste x = [x];;
 mettre_en_liste 1;;
let tête l = match l with
  []   -> failwith "tête : liste vide "
| e::r -> e;;  
let tête l = match l with
  []   -> failwith "tête : liste vide "
| e::_ -> e;;
tête [];;                               

tête [1; 2; 3];;

tête ["Bonjour"; "Merci"; "Au revoir"];; 

tête [ [1; 2]; [3] ];;

let reste l = match l with
| [] -> failwith "reste: liste vide"
| _::l' -> l';;
reste [];;  
reste [1; 2; 3];;
let zéro_en_tête l = match l with
| 0::_ -> true
| _ -> false;;
let deuxième l = match l with 
| x1::x2::l' -> x2
| _ -> failwith "deuxième: liste de moins de deux éléments";;
let rec zero_est_dans l =  match l with 
   [] -> false
 | 0::_ -> true
 | _::r -> zero_est_dans r;;
let rec lg l = match l with 
                  [] -> 0
                | _::r -> 1 + (lg r);;
[];;
(3,true);;
(5, ("toto", true), false);;
fst (1,2);; 
 fst (1,2,3);;
snd (1,2);;
(2+4, true && false);; 
 let pred_succ x = (x-1,x+1);;
 pred_succ 7;;
 let axe_des_x n = (n, 0.0);;
 axe_des_x 1.5;;
 let carré_norme v = match v with
  | (x,y) -> x *. x +. y *. y;;
 carré_norme (2.0, 3.0);;
 let proj1 (x,y) = x;;
 let u = (1.0, 2.5) in proj1 u;;
 proj1 (2,3);;                      
 proj1 ((3,4), 5);;
 proj1 ("un texte", true);;         
 proj1 (proj1 ((3,4), 5));;
 let proj2 (x, y) = y;;
let rec div (a,b)= 
  if b=0 then failwith "diviseur nul" else 
  if a<b then (0,a) else 
  match div ((a-b),b) with 
  | (q,r) -> (q+1,r);;
let rec div (a,b) = 
  if b=0 then failwith "diviseur nul" else 
  if a<b then (0,a) else 
  let (q,r) = div ((a-b), b) in (q+1,r);;
let f a = match a with
| (1, _) -> "cas 1"
| (_, 0) -> "cas 2"
| (x,y) -> if x=y then "cas 3" else "cas 4";;
 f (4,5);;
 f (1,1);;
 f (3,3);;
 f (1,0);;
 f (3,0);;
let identite = function x -> x ;;
identite 3;;
identite [1;3];;
(identite true, identite "toto");;
let f_constante = function x -> 1 ;;
f_constante (f_constante true);;