无法在Class中调用方法;获取运行时错误

Question

这里是我的代码

scala> class Subjects { 
    |  //The default Access Modifier of a vairable is 'public' #101 
    |  private var subjects:List[String] = Nil 
    | 
    |  //Always Specify Return type for Readability #103 
    |  //Here we are using Cons operator to prepend (Constant time) 
    |  //A method with Side effect is also called 'Procedure' #103 
    |  def addSubject(subject: String):Unit = { subjects = subject :: subjects } 
    | 
    |  def getSubjects():List[String] = subjects 
    | } 
defined class Subjects 


scala> 

scala> val obj = new Subjects 
obj: Subjects = Subjects@d7c7c22 

scala> obj.addSubject("Math") 
<console>:47: error: value addSubject is not a member of Subjects 
     obj.addSubject("Math") 

我想打电话给addSubject这是在classSubjects但得到编译错误的有效方法。我在这里错过了什么？

Answer 1

你是怎么在控制台上编写Subjects类的？使用:paste？

scala> val obj = new Subjects 
obj: Subjects = Subjects@62ddbd7e 

scala> obj.addSubject("Math") 

scala> obj.getSubjects() 
res1: List[String] = List(Math)