作业

object class05 {
  // 定义Point类，包含x、y坐标及题目要求的方法
  class Point(var x: Double, var y: Double) {
    // 方法1：判断所在象限
    def whereAmI(): String = {
      if (x == 0 && y == 0) "坐标原点"
      else if (x == 0) "在y轴上"
      else if (y == 0) "在x轴上"
      else if (x > 0 && y > 0) "第1象限"
      else if (x < 0 && y > 0) "第2象限"
      else if (x < 0 && y < 0) "第3象限"
      else "第4象限"
    }

    // 方法2：计算到原点的距离
    def getDist(): Double = math.sqrt(x * x + y * y)

    // 方法3：计算与另一个点的距离
    def fromPoint(other: Point): Double = {
      val dx = this.x - other.x
      val dy = this.y - other.y
      math.sqrt(dx * dx + dy * dy)
    }

    // 方法4：重写equals判断点是否相同
    override def equals(other: Any): Boolean = other match {
      case that: Point => this.x == that.x && this.y == that.y
      case _ => false
    }

    // 方法5：重写toString友好输出
    override def toString: String = s"Point(x=$x, y=$y)"
  }

  // 定义LabelPoint子类，继承Point并增加label属性
  class LabelPoint(val label: String, x: Double, y: Double) extends Point(x, y) {
    override def toString: String = s"LabelPoint(label='$label', x=$x, y=$y)"
  }

  // 测试逻辑
  def main(args: Array[String]): Unit = {
    // 测试Point类
    val point1 = new Point(3.0, 4.0)
    println(point1.whereAmI())    // 第1象限
    println(point1.getDist())     // 5.0

    val point2 = new Point(0.0, 0.0)
    println(point1.fromPoint(point2)) // 5.0
    println(point1 == point2)         // false

    // 测试LabelPoint子类
    val labelPoint = new LabelPoint("出生点", 0.0, 0.0)
    println(labelPoint)               // LabelPoint(label='出生点', x=0.0, y=0.0)
    println(labelPoint.whereAmI())    // 坐标原点
  }
}