Why “do…while” does not exist in F#

Question

I cannot find \"do...while...\"

I have to code like this:

let bubbleSort a=
    let n = Array.length a
    let mutable swapped = true
    let mutable i =         


        

Answer 1

It turns out to be quite easy to write a good enough do-while in F# as a higher-order function:

let doWhile f c =
    f ()
    while c () do
        f ()

Answer 2

Although a bit more verbose, you can use recursive functions to avoid the "do while" as in :

let swap (a:int[]) i j =
    let t = a.[i]
    a.[i] <- a.[j]
    a.[j] <- t

let rec bubbleSortAux a nMax j swapped =
  if j >= 0 && j <= nMax then
    if a.[j] > a.[j+1] then
      swap a j (j+1)
      bubbleSortAux a nMax (j+1) true
    else
      bubbleSortAux a nMax (j+1) false
  else
    swapped

let rec bubbleSortLoop a nMax =
  if bubbleSortAux a nMax 0 false then
    bubbleSortLoop a (nMax - 1)

let bubbleSort a =
    bubbleSortLoop a (a.Length - 2)