坐标系

package level02

object class11 {
  class Point(var x: Double, var y: Double) {
    // 简单实现位置判断
    def whereAmI(): String = {
      if (x > 0 && y > 0) "第一象限"
      else if (x < 0 && y > 0) "第二象限"
      else if (x < 0 && y < 0) "第三象限"
      else if (x > 0 && y < 0) "第四象限"
      else if (x == 0 && y == 0) "原点"
      else if (x == 0) "y轴"
      else "x轴"
    }

    def getDist(): Double = Math.sqrt(x * x + y * y)

    def fromPoint(other: Point): Double = {
      val dx = other.x - x
      val dy = other.y - y
      Math.sqrt(dx * dx + dy * dy)
    }

    override def toString: String = s"Point($x, $y)"

    // 简单判断坐标相等
    override def equals(obj: Any): Boolean = obj match {
      case p: Point => p.x == x && p.y == y
      case _ => false
    }
  }

  // 简化的带标签点（继承并传参）
  class LabelPoint(x: Double, y: Double, val label: String) extends Point(x, y)

  def main(args: Array[String]): Unit = {
    val p1 = new Point(1.0, 1.0)
    val p2 = new Point(1.0, 1.0)
    println(p1.whereAmI())    // 第一象限
    println(p1.getDist())     // 约1.414
    println(p1.fromPoint(p2)) // 0.0
    println(p1 == p2)         // true
  }
}