module Entier = struct
  type t = int
  let comp x y = x - y
end

module Chaine = struct
  type t = string

  let rec comprec s1 s2 i =
    if String.length s1 <= i then
      if String.length s2 <= i then 0
      else -1
    else
      if String.length s2 <= i then 1
      else
        if s1.[i] = s2.[i] then comprec s1 s2 (i+1)
        else (int_of_char s1.[i]) - (int_of_char s2.[i])

  let comp s1 s2 = comprec s1 s2 0
end

let _ = Entier.comp 2 4

let _ = Chaine.comp "aze" "aye"