Scala Reactive Programming

A tail-recursion example

Here, we will write a Scala Application to demonstrate the tail-recursion technique.

Scala's @tailrec annotation ensures that tail recursive functions are optimized by the Scala compiler, to avoid StackOverflowErrors:

package com.packt.publishing.recursion 
 
object TailRecursionApp extends App { 
 
  val list = List(1,2,3,4,5,6,7,8,9) 
  val list2 = tailRecursion(list) 
 
  println("Original List = " + list) 
  println("After Tail Recursion of List = " + list2) 
 
  @tailrec 
  def tailRecursion[A](listOfElements: List[A]): List[A] = { 
    def reverse(updatedList: List[A], originalList: List[A]):     List[A] = originalList match { 
      case Nil => updatedList 
      case head :: tail => reverse(head :: updatedList, tail) 
    } 
 
    reverse(Nil, listOfElements) 
  } 
 }