learning scala Function Recursive Tail Call

可以使用scala库，可以从字面上看出是在调用递归函数：

code

import scala.util.control.TailCalls._

  val arrayDonuts: Array[String] = Array("Vanilla Donut", "Strawberry Donut", "Plain Donut", "Glazed Donut")

  println("\nStep : How to define a tail recursive function using scala.util.control.TailCalls._")

  def tailSearch(donutName: String, donuts: Array[String], index: Int): TailRec[Option[Boolean]] = {

    if(donuts.length == index) {

      done(None) // NOTE: done is imported from scala.util.control.TailCalls._

    } else if(donuts(index) == donutName) {

      done(Some(true))

    } else {

      val nextIndex = index +

      tailcall(tailSearch(donutName, donuts, nextIndex)) // NOTE: tailcall is imported from scala.util.control.TailCalls._

    }

  }

  println("\nStep : How to call tail recursive function using scala.util.control.TailCalls._")

  val tailFound = tailcall(tailSearch("Glazed Donut", arrayDonuts, ))

  println(s"Find Glazed Donut using TailCall = ${tailFound.result}") // NOTE: our returned value is wrapped so we need to get it by calling result

  val tailNotFound = tailcall(tailSearch("Chocolate Donut", arrayDonuts, ))

  println(s"Find Chocolate Donut using TailCall = ${tailNotFound.result}")

resule:

Step : How to define a tail recursive function using scala.util.control.TailCalls._

Step : How to call tail recursive function using scala.util.control.TailCalls._

Find Glazed Donut using TailCall = Some(true)

Find Chocolate Donut using TailCall = None

巴特西

learning scala Function Recursive Tail Call

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