Scala program error

Question

When I run the below scala program in cloudera quickstart , I getting small error which I unable to rectify it. I am starter for scala programming.

object sort {
  def sort(s:Array[Int] => Unit ){
    var a=new Array[Int](3);
    a(0)=1;
    a(1)=1;
    a(2)=1;
    s(a);
  }

  def qsort(a:Int*){
    println("qsort printed");
  } 

  def main(args:Array[String]){
    sort(qsort);
  }
}

I am getting error

[cloudera@quickstart scalap]$ scalac sort.scala
sort.scala:12: error: type mismatch;
 found   : Seq[Int] => Unit
 required: Array[Int] => Unit
sort(qsort);
     ^
one error found

Please show me the solution.

It's more correct to follow Daniel's answer. My comment was more of a joke about cryptic syntax. — Kolmar
– Kolmar, Commented Oct 9, 2015 at 23:34

Daniel Langdon · Accepted Answer · 2015-10-09 23:09:26Z

2

It is simple, you can pass an instance of Array[Int] to a function that expects a Seq[Int], but not vice versa, as Array is more specific than Seq. To fix it, simply change tthe qsort definition to:

def qsort(a:Array[Int]){
  println("qsort printed");
}

or change definition of sort to receive a sequence. Either one will make the types match.

answered Oct 9, 2015 at 23:09

Daniel Langdon

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2 Comments

maroom Over a year ago

Thanks Daniel. Can you some suggestion from where to start to learn scala program . which gives simple way to teach.

Daniel Langdon Over a year ago

Sure. There are plenty of good books out there, or just learn by doing and googling. It kinda depends on if you know other languages or not. Check the coursera free online course from the very authors of scala here.

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