(* this is a comment *)
(* this is a (* nested *) comment *)

(* Copy & paste lines from this file to the interactive Ocaml environment
 * to see the output.
 * Or type 
 *    #use "01-Intro.ml";;
 * to load this file
 *)

(* Defining variables and functions with "let" *)
let x = 3;;
let sum x y = x + y;;

sum x 6;;

(* Printing *)
print_int 13;;
print_string "hello";;

(* Arithmetic and boolean operations *)
(* Use + - * / for integers
   and +. -. *. /. for floats 
*)

let d = 3.4 +. 6.7;;

3 > 4 || true;;

if x > 10 then print_string "greater" else print_string "smaller";;

(* Use parentheses generously *)
if x < 10 then 10 else 20 + 5;;   (* gives 10 *)
(if x < 10 then 10 else 20) + 5;; (* gives 15 *)

(* Sequencing is done with ; *)
print_int 42; print_string "\n";;

(* Characters are defined with single quotes *)
let c = 'a';;
int_of_char c;;
char_of_int 97;;

(* Use double quotes for strings, ^ for concatenation.
 * The String module contains useful functions 
 *)
let cons s = "hello "^s^"\n";;
print_string (cons "world");;
String.length "abcd";;
let j = int_of_string "123" + 7;; (* j = 130 *)