// val f =
//   Sub(
//      Sum(Prod(X(),X()),
//          Prod(Const(2),X()),
//      Const(7)
//   )
// val g = X()**2 + 2*X() - 7
// println(g(7.5))
// val deriv = g.derivata

sealed abstract class Fun {
    def apply(x:Double):Double =
        this match {
            case Const(i) => i
            case X() => x
            case Sum(a,b) => a(x)+b(x)
        }
}
case class Const(x:Double) extends Fun
case class X() extends Fun
case class Sum(a:Fun, b:Fun) extends Fun

object TestFun extends App {
    val f = Sum(X(),Const(7))
    println(f(2.0))
}

sealed abstract class Albero[T] {
  def conta:Int = this match {
    case AlberoV() => 0
    case AlberoNV(sx,r,dx) => 1+sx.conta+dx.conta
  }
}
case class AlberoV[T]() extends Albero[T]
case class AlberoNV[T](sx:Albero[T], r:T, dx:Albero[T]) extends Albero[T]

val v = AlberoNV(AlberoV(), 10, AlberoNV(AlberoV(),20,AlberoV()))

println(v.conta)