object class20 {
class Boss {
def power(): Unit = {
println("Boss 有权利...")
}
var car = "豪车"
}
class NoBody extends Boss{
}
def main(args: Array[String]): Unit = {
val b = new NoBody()
println(b.car)
b.power()
}
}
object class21 {
class Boss {
def test():Unit = {}
def power(): Unit = {
println("Boss 有权利...")
}
var car = "豪车"
}
class NoBody extends Boss {
def run():Unit = {
}
override def power():Unit = {
println("老莫,我想吃鱼了")
}
}
def main(args: Array[String]): Unit = {
val b = new NoBody()
println(b.car)
b.power()
b.run()
}
}
object class22 {
class Dog(var name:String,var age:Int) {
println(s"Dog${name} , ${age}构造器被调用")
}
class RuralDog(name:String,age:Int) extends Dog(name,age){
println("RuralDog的构造器...")
}
def main(args: Array[String]): Unit = {
new RuralDog("旺财",3)
}
}

object class20 {
class Point(var x: Double, var y: Double) {
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"
}
def getDist(): Double = math.sqrt(x * x + y * y)
def fromPoint(other: Point): Double = {
val dx = this.x - other.x
val dy = this.y - other.y
math.sqrt(dx * dx + dy * dy)
}
override def equals(other: Any): Boolean = other match {
case that: Point => this.x == that.x && this.y == that.y
case _ => false
}
override def toString: String = s"Point(x=$x, y=$y)"
}
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)"
}
def main(args: Array[String]): Unit = {
val point1 = new Point(3.0, 4.0)
println(point1.whereAmI())
println(point1.getDist())
val point2 = new Point(0.0, 0.0)
println(point1.fromPoint(point2))
println(point1 == point2)
val labelPoint = new LabelPoint("出生点", 0.0, 0.0)
println(labelPoint)
println(labelPoint.whereAmI())
}
}