二维游戏（火影）创作

object w42 { class Point(var x: Double, var y: Double) { // 方法1：判断象限 def whereAmI(): String = { 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 if (x > 0 && y < 0) "第4象限" else "在坐标轴上" }

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

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

// 方法4：重写 equals 判断是否为同一点
override def equals(other: Any): Boolean = {
  val o = other.asInstanceOf[Point]
  o.x==x && o.y==y
}

def canEqual(other: Any): Boolean = other.isInstanceOf[Point]

// 方法5：重写 toString 友好输出信息
override def toString: String = s"${x},${y}"

} class LabelPoint(val color: String, x: Double, y: Double) extends Point(x, y) { override def toString: String = s"${color}:${x}, ${y}" println(s"LabelPoint构造器${color}") }

def main(args: Array[String]): Unit = { val s1 =new Point(3.0,4.0) val s2 = new Point(6.0,8.0) println(s1.whereAmI()) println(s1.getDist()) println(s1.fromPoint(s2)) println(s1==s2) println(s1.toString) val s3 =new LabelPoint("black",1.0,0) val s4 =new LabelPoint("black",2.0,0) println(s3.whereAmI()) println(s3.getDist()) println(s3.fromPoint(s4)) println(s3==s4) println(s3.toString) }

只有我们才是真投入