Scala script which demonstrates how tail recursion can be applied in Scala

Recursion.scala

  /*
  * Scala script which demonstrates how tail recursion can be applied in
  * Scala and what the value of tail recursion is in terms of applicability
  * The functions in this example add all a values (which can be divided by 3)
  * up to a given max. 
  */
  
  // help function to find the first value which can be divided by 3
  def findStart(upTo:Int):Int = {
    if (upTo%3==0 || upTo<0) upTo
    else findStart(upTo-1)
  } 
  
  // recursive implementation
  def sumMod(upTo:Int):Int = {    
    def sumModInt(upTo:Int):Int = {
      if(upTo<0) 0
      else upTo + sumModInt(upTo-3)
    }
    sumModInt(findStart(upTo))
  }
  
  // implementation using the scala libs
  def sumModScalaLib(end:Int) = {
    0 to end by 3 sum
  }
  
  // tail-recursive implementation
  def sumModTail(upTo:Int):Int = {
    def sumModInt(upTo:Int, sum:Int):Int = {
      if(upTo<0) sum
      else sumModInt(upTo-3, upTo + sum)
    }
   sumModInt(findStart(upTo), 0);
  }  

  // function to measure the time a function application takes
  def time[T](code: => T):(Long, T) = {
    import System.{currentTimeMillis => cTime}
    val start = cTime
    val returnValue = code
    (cTime-start, returnValue)
  }
  
  def run(upTo:Int) {
    val tailRec = time{
      sumModTail(upTo)
    }
    printf("tail recusion: %s \n", tailRec)

    val lib = time{
      sumModScalaLib(upTo)
    }
    printf("scalaLib: %s \n", lib)
    
    val rec = time{
      sumMod(upTo)
    }
    printf("recusion normal: %s \n", lib)

  }