Scala Error Import - scala

Question

I'm learning Scala, and I was attempting to import from 2 scrips in different classes, but, I get an error, and I don't know why.
This class, in Summer.scala, is where I try to import the singleton object from class ChecksumAccumulator.
import ChecksumAccumulator.calculate
object Summer{
def main(args: Array[String]): Unit= {
for (arg <- args)
println(arg + " : " + calculate(arg))
}
}
Class ChecksumAccumulator, with the singleton object ChecksumAccumulator.
object ChecksumAccumulator {
/*
When a singleton object shares the same name
with a class, it is called that class's companion object.
*/
private val cache = mutable.Map.empty[String, Int]
def calculate(s: String): Int =
if (cache.contains(s))
cache(s)
else {
val acc = new ChecksumAccumulator
//The object with the same name of the class can acces to the private members.
//println(acc.sum)
for (c <- s)
acc.add(c.toByte)
val cs = acc.checksum()
cache += (s -> cs)
cs
}
def showMap() : Unit = {
for(base:String <- cache.keys)
println(cache(base))
}
//def showMap(): String = { var cadena = cache("Every value is an object.") + " "+ cache("Every value is an object. per second time!!"); cadena }
}
This script throw this mistake
scala Summer.scala
Summer.scala:8: error: not found: object ChecksumAccumulator import
ChecksumAccumulator.calculate ^ Summer.scala:14: error: not found:
value calculate println(arg + " : " + calculate(arg)) ^ two errors
found

Answer 1

It seems like it's a duplicated question, but I can't yet mark questions as duplicated nor comment on them.
If that is all your code, it means you're missing:
class ChecksumAccumulator { ... }
Because you're trying to create an instance of this class:
val acc = new ChecksumAccumulator
And it's impossible to achieve with just:
object ChecksumAccumulator { ... }
Check out this answer about exactly the same code example. There is the missing definition of class ChecksumAccumulator :
https://stackoverflow.com/a/8681616/5100014
Just make sure to paste it into the same file with object ChecksumAccumulator