Scala内部类的运用

内部类：定义在类里面的类（内部类可以访问私有成员用它来操作类的私有成员，封闭性更好）

class Student{
  var age=18
  def say():Unit={

  }
  class Book{
    val bookName: Any = "Scala程序设计"
    }
  }

object Test19 {
  def main(args: Array[String]): Unit = {
    val s1=new Student()
    val book1=new s1.Book()

    println(book1.bookName)
  }

}



输出：Scala程序设计

class Car2 {
  private var speed=100
  val color="red"
  //
  class Engin(var maxSpeed:Int){
    def acc():Unit={
      speed+=10
      if (speed>maxSpeed){
        speed=maxSpeed
      }
      println("speed",speed)
    }
    def sub():Unit={
      speed-=10
    }
  }

  override def toString: String = {

    s"当前的速度是${speed}"
  }
}
object Test19_1{
  def main(args: Array[String]): Unit = {
    val c=new Car2()
    var engin=new c.Engin(maxSpeed=120)
    engin.acc()
    engin.acc()
    engin.acc()
    println(c)
    engin.sub()
    println(c)

  }

}

输出：(speed,110)
(speed,120)
(speed,120)
当前的速度是120
当前的速度是110