Function not returning value when called-CodePudding

So, I'm a bit new to Scala, and I don't really understand how it reads code, compared to other languages.

Take this simple example:

@main
  def roll():Int =
    var x:Int = (math.random*6 1).toInt
    return x
  def print = 
    for i <- 1 to 10 do 
      println(roll())

The above code returns nothing, however, should I flip the methods (put print "method" before "roll"), it will now work. I find this incredibly strange. Where have I done wrong? I just simply want to call a method/function that randomizes a number, and print it using a new function to call it. Anyone who can help me?

CodePudding user response：

@main annotation is applied to method (one, the following after it), i.e. for :

@main
def roll():Int =
  var x:Int = (math.random*6 1).toInt
  return x

def print = 
  for i <- 1 to 10 do 
    println(roll())

Your main method will be roll and only it will be invoked during program execution. And print is just a declared method which is not called.

And when you "flip them":

@main
def print = 
  for i <- 1 to 10 do 
    println(roll())

def roll():Int =
  var x:Int = (math.random*6 1).toInt
  return x

print becomes the main method, so it is invoked and it calls the declared roll method in the loop.