Carlos's questions

Hello everyone, I just started using Scala and I have a problem that I can't get out of, I need to find an element within an array by recursion with an auxiliary function called search, which takes parameters from the left and right ends. The truth is that I am very overwhelmed because the compiler does not give me any error, it just seems that it does not enter the BinaryRec search method when I put it in the println. First of all, thanks for your help, this is what I have so far:

  import scala.io.StdIn._

def busquedaBinariaRec[A](x:A,xs:Array[A])(implicit ord : Ordering[A]): Any ={
  //implementarlos recursivamente sin usar bucles
  import ord._
  buscar(0, xs.length -1)
  def buscar (izq:Int, der:Int):Any = {
    var indice : Option[Int] = None
    var izq = 0
    var der = xs.length -1
    if (indice.isEmpty && izq <= der) {
      val cen = (izq+der)/2
      val y = xs(cen)
      if (x==y) indice=Some(cen)
      else if (x>y)
       izq = cen +1
      else
        der = cen-1
    }
   return indice 
  }

}
  println("¿Cual es el Array?")
val xs = Array[Int](1, 5, 6, 10, 14, 20, 50) //El Array sobre el que queramos realizar la busqueda lo cambiamos aqui
println(xs.mkString("Array(", ", ", ")"))
println("Introduce el elemento que quieras buscar")
val n: Int = readInt()
println(busquedaBinariaRec(n, xs))
}

I am doing a programming exercise in Haskell, in which I give some values ​​in a list, for example [1, 2, 2, 3, 4] and it should be as follows [1, 4, 3, 4]. So far the program works without problems for me with the following code:

sustituirSumando [x,y] 
              | x==y = [x+y]
              | otherwise = [x,y]
sustituirSumando [x,y,z] 
              | x==y = [x+y,z]   
              | y==z = [x,y+z]
              |otherwise = [x,y,z] 
sustituirSumando (x:y:xs) 
               | x==y = (x+y) : sustituirSumando (xs)                
               | otherwise = x: sustituirSumando (y:xs)

Where I don't know how to proceed is in the following supposed example [1, 2, 2, 4, 5] here the list should be as follows [1, 8, 5] but in my code it remains [1, 4, 4, 5]. Thanks in advance.