let random_char chars =
  let index = Random.int (String.length chars) in
  String.get chars index

let generate_password length use_special use_digits use_upper use_lower =
  let chars = 
    (if use_special then "!@#$%^&*()" else "") ^
    (if use_digits then "0123456789" else "") ^
    (if use_upper then "ABCDEFGHIJKLMNOPQRSTUVWXYZ" else "") ^
    (if use_lower then "abcdefghijklmnopqrstuvwxyz" else "") in
  String.init length (fun _ -> random_char chars)

let () =
  Random.self_init ();
  print_string "Enter password length: ";
  let length = read_int () in
  print_string "Include special characters? (y/n): ";
  let use_special = read_line () = "y" in
  print_string "Include digits? (y/n): ";
  let use_digits = read_line () = "y" in
  print_string "Include uppercase letters? (y/n): ";
  let use_upper = read_line () = "y" in
  print_string "Include lowercase letters? (y/n): ";
  let use_lower = read_line () = "y" in
  let password = generate_password length use_special use_digits use_upper use_lower in
  Printf.printf "Generated password: %s\n" password