word pair

gistfile1.scala

object WordPair {

  def main(args: Array[String]) = {
    val line = "Android is a Linux-based operating system designed primarily for touchscreen mobile devices".split(" ").toList
    val pairs = wordPair(line)
    println(pairs)
  }

  def wordPair(line: List[String]): List[(String, String)] = line match {
    case Nil => Nil
    case x :: Nil =>  Nil
    case x :: y :: tail => (x, y) :: wordPair(y :: tail)
  }

}