Cannot compile file in Scala

Question

From an example in book "Begining in Scala", the script is:

import scala.collection.mutable.Map

object ChecksumAccumulator {
 private val cache=Map[String,Int]()
 def calculate(s: String):Int =
   if(cache.contains(s))
     cache(s)
   else{
     val acc = new ChecksumAccumulator
     for(c <- s)
       acc.add(c.toByte)
     val cs=acc.checksum
      cache+= (s -> cs)
     cs
  }
}

but, when I tried to compile this file $scalac ChecksumAccumulator.scala, then generate an error, "not found: type ChecksumAccumulator val acc = new ChecksumAccumulator", any suggest?

Thanks,

Answer 1

'object' keyword defines a singleton object, not a class. So you can't new an object, the 'new' keyword requires a class.

check this Difference between object and class in Scala