Is there anything wrong with my code

Question
1

Is there anything wrong with my code

Here’s my code:

import util.Random
println((1 to 5).map(_ => Random.nextInt))

Here’s the error:

[error] ./Documents/VS Code/Randomnumberlist/Randomnumberlist.scala:2:1
[error] Illegal start of toplevel definition
[error] println((1 to 5).map(_ => Random.nextInt))
[error] ^^^^^^^
Error compiling project (Scala 3.6.3, JVM (23))
Compilation failed
2

Well, obviously there is or you wouldn’t get the error you got. If you want to play with code like that, you should probably be using Scastie which has a mode which does what you tried to do.

You can see exactly what you wrote working here:
Scastie - An interactive playground for Scala.

If you’d rather not depend on an online tool, it depends how you executed it. This isn’t a normal Scala file–you need an object with a main method, at a minimum. But there is a script mode in scala-cli (which is also scala if you have 3.6 and are trying to run the file using scala as a command); if you save your file as .sc and do scala-cli run, it will wrap the code in the appropriate way for the JVM and do what you want.

For example:

~/Code/scala/temp$ scala-cli run A.scala
Compiling project (Scala 3.6.3, JVM (17))
[error] ./A.scala:2:1
[error] Illegal start of toplevel definition
[error] println((1 to 5).map(_ => Random.nextInt))
[error] ^^^^^^^
Error compiling project (Scala 3.6.3, JVM (17))
Compilation failed
~/Code/scala/temp$ mv A.scala A.sc
~/Code/scala/temp$ scala-cli run A.sc
Compiling project (Scala 3.6.3, JVM (17))
Compiled project (Scala 3.6.3, JVM (17))
Vector(2126242071, -375641670, -392946654, -2018029152, -544726030)

The minimal wrapping you need for it to be a valid .scala file and to run the code (not in script mode) is shown here:

~/Code/scala/temp$ cat B.scala
import util.Random

object Main:
  def main(args: Array[String]): Unit =
    println((1 to 5).map(_ => Random.nextInt))

~/Code/scala/temp$ scala-cli run B.scala
Compiling project (Scala 3.6.3, JVM (17))
Compiled project (Scala 3.6.3, JVM (17))
Vector(-920095178, -74663704, -476828234, -1424034221, 1497006213)
3 Likes
3

Or like so:

import util.Random

@main
def whateverYouWantToCallIt =
  println((1 to 5).map(_ => Random.nextInt))
1 Like
4

It works now, thanks