RecursiveLinearSearch.scala

import scala.annotation.tailrec

@tailrec
def search(data: List[Int], value: Int, index: Int = 0): Int = {
  if (index >= data.size) -1
  else if (data(index) == value) index
  else search(data, value, index + 1)
}

object Main extends App {
  val data: List[Int]    = List(9, 2, 6, 1, 3, 5, 4, 7, 8)
  val values: List[Int]  = List(9, 3, 8, 246)
  val results: List[Int] = values.map(v => search(data, v))

  values
    .zip(results)
    .foreach((value, result) => println(s"Value: $value -> Index: $result"))
}