寒假打卡16

 

 

 

import scala.io.StdIn
object spark2_1
{
  def main(args: Array[String])
  {
    var Sum=0.0
    println("请输入q的值")
    var q:Int=StdIn.readInt()
    var i=1.0
    while(Sum<q)
    {
      Sum=Sum+(i+1)/i
      i=i+1
    }
    println("--------------------------")
    printf("级数的前n项和为:%f \n",Sum)
  }
}

 

 

 

 

case class Point(var x:Double,var y:Double)extends Drawable
{
  def shift(deltaX:Double,deltaY:Double)
  {
    x+=deltaX;
    y+=deltaY
  }
}

trait Drawable
{
  def draw(){println(this.toString)}
}

abstract class Shape(var location:Point)//location是Shape的一个可变字段
{
  def moveTo(newLocation:Point)//默认实现，只是修改位置
  {
    location=newLocation
  }
  def zoom(scale:Double)
}

class Line(beginPoint:Point,var endPoint:Point)extends Shape(beginPoint)with Drawable
{
  override def draw()
  {
    println(s"Line:(${location.x},${location.y})--(${endPoint.x},${endPoint.y})")//按规定格式重载click
  }

  override def moveTo(newLocation:Point)
  {
    endPoint.shift(newLocation.x-location.x,newLocation.y-location.y)//直线移动时，先移动另外一个端点
    location=newLocation //移动位置
  }

  override def zoom(scale:Double)
  {
    val midPoint=Point((endPoint.x+location.x)/2,(endPoint.y+location.y)/2) //求出中点，并按中点进行缩放
    location.x=midPoint.x+scale*(location.x-midPoint.x)
    location.y=midPoint.y+scale*(location.y-midPoint.y)
    endPoint.x=midPoint.x+scale*(endPoint.x-midPoint.x)
    endPoint.y=midPoint.y+scale*(endPoint.y-midPoint.y)
  }
}

class Circle(center:Point,var radius:Double)extends Shape(center)with Drawable
{
  override def draw() //按规定重载click
  {
    println(s"Circle center:(${location.x},${location.y}),R=$radius")
  }

  override def zoom(scale:Double)
  {
    radius=radius*scale //对圆的缩放只用修改半径
  }
}

object spark2_2
{
  def main(args:Array[String])
  {
    val p=new Point(10,30)
    p.draw

    val line1=new Line(Point(0,0),Point(20,20))
    line1.draw
    line1.moveTo(Point(5,5))
    line1.draw
    line1.zoom(2)
    line1.draw

    val cir=new Circle(Point(10,10),5)
    cir.draw
    cir.moveTo(Point(30,20))
    cir.draw
    cir.zoom(0.5)
    cir.draw
  }

}

 

 

 

 

object spark2_3
{
  def main(args:Array[String])
  {
    //假设数据在当前目录下
    val inputFile=scala.io.Source.fromFile("H:/scala/test2_3.txt")

    //"\\s"是字符串正则表达式，将每行按空白字符（包括空格/制表符）分开
    //由于可能涉及多次遍历，通toList将Itertor装为List
    //originalData的类型为List[Array[String]]
    val originalData=inputFile.getLines.map{_.split{"\\s+"}}.toList

    val courseNames=originalData.head.drop(2) //获取第一行中的课程名
    val allStudents=originalData.tail //去除第一行剩下的数据
    val courseNum=courseNames.length


    def statistc(lines:List[Array[String]])=
    {
      //for推导式，对每门课程生成一个三元组，分别表示总分，最低分和最高分
      (for(i<- 2 to courseNum+1) yield
        {
          //取出需要统计的列
          val temp =lines map
            {
              elem=>elem(i).toDouble
            }
          (temp.sum,temp.min,temp.max)
        })map{case(total,min,max)=>(total/lines.length,min,max)} //最后一个map对for的结果进行修改，将总分转为平均分
    }

    //输出结果函数
    def printResult(theresult:Seq[(Double,Double,Double)])
    {
      //遍历前调用zip方法将课程名容器和结果容器合并，合并结果为二元组容器
      (courseNames zip theresult)foreach
        {
          case(course,result)=>
            println(f"${course+":"}%-10s${result._1}%5.2f${result._2}%8.2f${result._3}%8.2f")
        }
    }

    //分别调用两个函数统计全体学生并输出结果
    val allResult=statistc(allStudents)
    println("course    average    min    max")
    printResult(allResult)

    //按性别划分为两个容器
    val (maleLines,femaleLines)=allStudents partition
      {
        _(1)=="male"
      }

    //分别调用两个函数统计男学生并输出结果
    val maleResult=statistc(maleLines)
    println("course    average    min    max")
    printResult(maleResult)

    //分别调用两个函数统计女学生并输出结果
    val femaleResult=statistc(femaleLines)
    println("course    average    min    max")
    printResult(femaleResult)

  }

}