// Scala is about expressions

//

//

1 + 2

val r1 = 1 + 2

val r2 = r1 * r1

val new_list = 

  for (n <- (1 to 10).toList) yield n * n

def my_not_equal(x: Int, y: Int) : Boolean = {

 !(x == y)

}

// why return is not needed in Scala

def sum_even(ls: List[Int]): Int = {

  val aux = for (x <- ls) yield {

    if (x % 2 == 0) x else 0

  }

  aux.sum

}

sum_even(List(1,2,3,4,5,6))

def sum_return(ls: List[Int]): Int = {

  val aux = for (x <- ls) yield {

    if (x % 2 == 0) (return x) else (return 0)

  }

  aux.sum[Int]

}

sum_return(List(2,3,4,5,6))

// replace subexpressions should not 

// change the meaning, but with return it does:

def sq1(n: Int): Int = n * n

def sq2(n: Int): Int = return n * n

def sum_squares(ls: List[Int]): Int = {  

  (for (n <- ls) yield (return n * n)).sum[Int]

}

sum_squares(List(1,2,3,4,5,6))