I'm just learning scala, and I wrote the "hello,world" program like this:

object HelloWorld {
    def main(args: Array[String]) {
        println("Hello, world!")
    }
}

I saved it to a file named "helloworld.scala"

Now I run it in the console:

scala helloworld.scala

But nothing outputed. I thought it will output "Hello, world". Why?

PS

If I modify the content to:

println("Hello, world")

and run again, it will output "hello,world".

if you want to run your code as a script (by using scala helloworld.scala) you have to tell scala where your main method is by adding the line

  HelloWorld.main(args)

to your code

the second option you have is compiling the script by using scalac helloworld.scala and then calling the compiled version of your class using scala HelloWorld

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