Solution in F# for http://www.spoj.com/problems/TEST/

test.fs

open System

let rec readUntilDone input =
    match input with
    | "42" -> 0
    |_     -> Console.WriteLine(input)
              readUntilDone(Console.ReadLine())

[<EntryPoint>]
let main args =
    readUntilDone(Console.ReadLine())