队列

import scala.collection.immutable.Queue
import scala.collection.mutable

object Test18_Queue {
  def main(args: Array[String]): Unit = {
    //创建一个可变队列
    val queue = new mutable.Queue[String]()
    queue.enqueue("a", "b", "c")
    //入队
    println(queue)
    //出队，先进先出
    println(queue.dequeue())
    println(queue)
    println(queue.dequeue())
    println(queue)

    queue.enqueue("d", "e")
    println(queue.dequeue())

    //不可变队列
    val queue1 = Queue("a", "b", "c")
    val queue2 = queue1.enqueue("d")
    println(queue1)
    println(queue2)
  }
}