finmd

(* 1. Write a function find : string array -> string -> int option such that find a w = Some idx if a.(idx) = w and find a w = None if there is no such index. *)

let find (str_arr : string array) (str : string) : int option =
  let start = 0 in
  let rec found (index: int) (arr: string array) : int option =
    if index < Array.length(arr)
    then
      if str = arr.(index)
      then Some index
      else found (index + 1) arr
    else None
  in
  found start str_arr
;;