UnlimitedFactorial.fs

let bigFactorial n=
    let rec loop x acc =
        match x with
        | x when x = 0I || x= 1I -> acc
        | _ ->  loop (x-1I) (acc*(x-1I))
    loop n 1I


[<EntryPoint>]
let main argv = 
    let timer = System.Diagnostics.Stopwatch()
    timer.Start()
    let result = (bigFactorial 100000I)
    timer.Stop()
    printfn "%A in %dms" result timer.ElapsedMilliseconds
    System.Console.ReadKey() |> ignore
    0