ПСЯПР четвертая

Lab4.scala

object Main extends App {
  def processList1(list: List[(Int, Int)]): List[Option[Double]] =
    list.map(elem => {
      val (c, z) = elem
      z match {
        case 0 => None
        case _ => Some(c*1.0/z)
      }
    })

  val result = processList1(List((1, 1), (2, 1), (1, 3), (0, 1), (5, 0)))

  println(result)

  def processList2(list: List[Option[Double]]): List[String] =
    list.map {
      case Some(s) => "Результат деления=" + s
      case None => "Деление на 0 невозможно"
    }

  println(processList2(result))

  abstract class Tree
  case class Leaf(operand:Int) extends Tree
  case class BinaryOperation(operation: String, left:Tree, right:Tree) extends  Tree
  case class UnaryOperation(operation: String, operand: Tree) extends  Tree

  val tree = BinaryOperation("+",
    BinaryOperation(
      "*",
      Leaf(2),
      Leaf(4)
    ),
    BinaryOperation(
      "/",
      Leaf(6),
      Leaf(2)
    )
  )


  val tree2 = UnaryOperation("++", Leaf(6))

  def syntaxTreeToRPN(tree: Tree): String = {
    tree match {
      case Leaf(value) => value.toString
      case UnaryOperation(operation, operand) =>
        syntaxTreeToRPN(operand) +  " "+ operation
      case BinaryOperation(operation, left, right)=>
        syntaxTreeToRPN(left) + " " + syntaxTreeToRPN(right) + " "+ operation
      case _ => ""
    }
  }

  println(syntaxTreeToRPN(tree))
  println(syntaxTreeToRPN(tree2))
}