Scala试题

作业：定义一个伴生类和伴生对象Student

定义伴生类Student

  属性：name、age、score private权限

  定义getter和setter

定义伴生对象Student

  定义apply和unapply方法

  定义一个object对象，进行测试（分别调用apply方法和unapply方法）

---

//定义伴生类 Student
class Student{
  private var name:String=_
  private var age:Int=_
  private var score:Double=_
  //辅助构造器
  def this(name:String,age:Int,score:Double){
    this()
    this.name=name
    this.age=age
    this.score=score
  }
  //定义getter
  def _name=name
  def _age=age
  def _score=score
  //定义setter
  def name_(name:String): Unit ={
    this.name=name
  }
  def age_(age:Int): Unit ={
    this.age=age
  }
  def score_(score:Double): Unit ={
    this.score=score
  }
}
//定义伴生对象 Student
object Student{
  def apply(name:String,age:Int,score:Double)={
    println("自动调用 apply")
    new Student(name,age,score)
  }
  def unapply(stu:Student):Option[(String,Int,Double)]={
    println("自动调用 unapply")
    Some((stu.name,stu.age,stu.score))
  }
}
object New {
  def main(args: Array[String]): Unit = {
    val stu1:Student=Student("anyiya",20,60.8)
    //stu1.show()
    stu1 match {
      case Student(a,b,c) => println(a,b,c)
    }
    println(s"getter方法展示：${stu1._name},${stu1._age},${stu1._score}")

    println("使用setter方法")
    stu1.age_(22)
    stu1.score_(97.8)
    println(s"getter方法展示：${stu1._name},${stu1._age},${stu1._score}")
  }
}

期末测试题

求1~100所有能被3整除的数字和，结果存入D:/data.txt

import java.io.PrintWriter
import scala.io._
object New {
  def main(args: Array[String]): Unit = {
    var sum=0
    for(i <- 0 to 100 ){
      if(i %3 ==0)
        sum=sum+i
    }
    var out = new PrintWriter("D:\\data.txt")
    out.print(sum)
    out.close()
  }
}

定义一个Person类

    定义一个Action特质，包含一个方法thinking，调用则显示正在思考......

    定义一个Persion类，包含一个public的属性name:String，一个无参的主构造器和有参数的辅助构造器。继承Action特质。

trait Action{
  def thinking()={
    println("正在思考......")
  }
}
class Person() extends Action{
  var name:String=_
  def this(name:String){
    this()
    this.name=name
  }
  override def thinking(): Unit = {
    print(name)
    super.thinking()
  }
}
object New {
  def main(args: Array[String]): Unit = {
    var per1:Person = new Person("anyiya")
    per1.thinking()
  }
}