open System.Diagnostics

​

let ticks_to_ns ticks =  (float ticks / float Stopwatch.Frequency) * (1.0E+9)

​

let n = 100000

​

let FizzBuzz2 max =

    let mutable state = 0

    for i = 0 to max do

        if i % 5 = 0 || i % 3 = 0 then state <- state + i

    state

​

do FizzBuzz2 0

​

let sw = System.Diagnostics.Stopwatch.StartNew()

do FizzBuzz2 n

sw.Stop()

​

printfn "FizzBuzz2 executed in %f nanoseconds (n = %i)" (ticks_to_ns sw.ElapsedTicks) n