一天一段scala代码（八）

package examples


class Person8
{
    var name:String=""
    def this(name:String)
    {
      this()//一定要先调用主构造器.每个辅助构造器最终都会调用主构造器
      this.name=name
    }
    override def toString=
    {
       "name:"+name
    }
    def show=
    {
      println("Person:"+toString)
    }
}

class Employee(name:String,salary:Double) extends Person8(name:String) //只有主构造器能够调用超类的构造器
{
    override def toString=
    {
       "name:"+name+",salary:"+salary
    }
    
    override def show=
    {
      println("Employee:"+toString)
    }
    
  
}

object Example8 extends App{
  val t1 = new Person8("linger")
  println(t1)
  t1.show
  
  val t2 = new Employee("linger",15)
  println(t2)
  t2.show
  
  val t3:Person8 = t2   //这里跟c++不一样阿,c++必须是虚函数,才会呈现多态.scala里没有虚函数,所有函数只要被override了都会呈现多态
  println(t3)
  t3.show
}

name:linger
Person:name:linger
name:linger,salary:15.0
Employee:name:linger,salary:15.0
name:linger,salary:15.0
Employee:name:linger,salary:15.0