why scala function parameters can't reassign to a new One?

Question

  class NodeL(a :Int){
    var value = a
  }

  def change(x :NodeL) = {
    if(x == null) x = new Node
  }

when I use code above ,compiler give me an error "reassignment to val" in the statement "if(x == null) x = new Node" why?

By default, method parameters are `val` in Scala. – justAbit Jun 23 '16 at 04:13 — justAbit, Jun 23 '16 at 04:13
@SudhirSingh Not "by default", they can't be `var` at all. – Alexey Romanov Jun 23 '16 at 06:32 — Alexey Romanov, Jun 23 '16 at 06:32

Raphael Roth · Answer 1 · 2016-06-23T06:33:47.203

5

You can't, method parameters are immutable in scala (i.e., they are vals)

edited Jun 23 '16 at 06:33

answered Jun 23 '16 at 04:19

Raphael Roth

1 Answers1