f# lab 1

exception UJEMNY_ARGUMENT ;;

let rec ( ^^ ) b p =
    if p = 0 then 1
    elif p < 0 then -1
    else b * (b ^^ (p - 1))

let rec suma m n =
    if n = 0 then m
    elif n > 0 then m + n + suma m (n - 1)
    else raise UJEMNY_ARGUMENT

let tylkoMaleLitery s =
    Array.forall(fun el -> System.Char.ToLower el = el) (Seq.toArray s)

let rec mRn m n =
    if n = 0 then 0
    elif n = 1 then m
    elif n > 0 then m + mRn m (n - 1)
    else raise UJEMNY_ARGUMENT

let rec wystOdItego (str: string, i, ch) =
    if str = "" then 0
    elif i <= str.Length then 0
    elif (str.Substring i).StartsWith ch then 1 + wystOdItego (str.Substring 1) 0 ch
    else -1


[<EntryPoint>]
let main _ =
    printf "^^: %d %d %d\n" (2 ^^ 4) (2 ^^ 0) (2 ^^ -1)
    printf "suma: %d %d %d\n" (suma 2 4) (suma 2 0) (suma 2 -1)
    printf "tylkoMaleLitery abc %b Abc %b '' %b" (tylkoMaleLitery "abc") (tylkoMaleLitery "Abc") (tylkoMaleLitery "")
    printf "\nmRn %d %d %d %d" (mRn 4 5) (mRn 4 0) (mRn 4 1) (mRn -4 2)
    printf "\nwystOdItego %d" (wystOdItego "abccab" 2 "a")
    0