//父類(lèi)必須用open修飾，才能夠被繼承
open class Person(val name:String) {
    var age = 0
    //父類(lèi)定義的函數(shù)，必須有open修飾，子類(lèi)才能復(fù)寫(xiě)
    open fun doWork(){
        println("do nothing")
    }
}

class Student(name: String) : Person(name) {
    override fun doWork() {
        println("do homework")
    }
}
fun main() {
    val student = Student("HanMei")
    student.age = 20
    println(student.name)
    println(student.age)
    student.doWork()
}

    val student = Student("HanMei")
    println(student is Student)
    println(student is Person)
    println(student is Any)

    Student student = new Student();
    System.out.println(student instanceof Student);
    System.out.println(student instanceof Person);

public open class Any {
    public open operator fun equals(other: Any?): Boolean
    public open fun hashCode(): Int
    public open fun toString(): String
}

class Student(name: String) : Person(name) {
    override fun doWork() {
        println("do homework")
    }
    override fun toString(): String {
        return "name:$name age:$age"
    }
    override fun hashCode(): Int {
        return super.hashCode()
    }
    override fun equals(other: Any?): Boolean {
        return super.equals(other)
    }
}

fun sayHello(p: Person) {
    println("Hello," + p.name)
}

    val student = Student("HanMei")
    sayHello(student)
    sayHello((student as Person))