A tutorial to quickly revise Scala syntax and features

Helloworld.scala

/*
 * Scala - Scalable Language, hybrid functional Programming language
 * Integrates features of OOP and functional languages
 * Compliled on JVM
 * Can use all classes of JAVA SDK and also own custom classes
 * Some different features from JAVA
 * 1. All types are objects
 * 2. Tpye inference
 * 3. Nested Functions
 * 4. Functions are also objects (like python)
 * 5. Closures (like python) - a function whose return value depends on value of one ore more variables declared outside this function.
*/
object HelloWorld { 
   def main(args: Array[String]) {
      
     //declare variables -  mutable
     var myVar : String = "First variable"
     
     //declare values - immutable
     val myVal : String = "First value" 
     
      //type inference
      var a = 7
      var b = 6L
      var c = 6.76
      var d = 6.98F
      var ans = """
multiline string
a is int, b is long, c is double, d is float 
        """
      println(ans)
      
      //declaring a tuple - immutable
      var tup = (40,"hello")
      println(tup._1)
      
      //multiple assignments using tuple
      val (v1:Int , v2) = (40,42.7F)
      println(v1,v2)
      
      //creating objects
      var point = new Point(30,50)
      point.move(2,4)
      point.move(3,-1)
      
       //for is different
       var x = 0
       for(x <- 1 to 10){ print(x+" ") }
       println()
       for(x <- 1 until 10){ print(x+" ") }
       println()
       
       val numList = List(5,6,7)
       //nested loop using for
       for(a <- 1 to 3; b <- numList ){
         print((a,b)+" ")
       }
       println()
       
       //for with yield
       var retVal = for( x <- numList
           if x %3 != 0; if x < 10  
       ) yield x 
       
       println(retVal)
     
      
      
   }
}

//class name works as class constructor
class Point(val xc:Int, val yc:Int){
  var x = xc
  var y:Int = yc
  
  def move(dx:Int, dy:Int){
    x = x+dx
    y = y+dy
    println("Current position: "+(x,y))
  }
}

InheritenceExample.scala

class ThreeDPoint(override val xc: Int, override val yc: Int, val zc: Int) extends Point(xc,yc){
  var z : Int = zc
  //if function do not return anything use Unit 
  //procedure
  def move(dx: Int, dy: Int, dz: Int) : Unit = {
    x+=dx
    y+=dy
    z+=dz
    println("Current position: "+(x,y,z))
  }
  
  //function
  def getPosition(): (Int, Int, Int) = {
    return (x,y,z)
  }
}

//scalas singleton object
object InheritenceExample {
  def main(args: Array[String]){
     var tdp = new ThreeDPoint(10,20,30)
     tdp.move(1,2,3)
     tdp.move(3,4,5)
     
     print("I am at "+tdp.getPosition())
  }
}

/*
 * Private members are visible only inside the class or object
 * Protected member is only accessible from subclass of the class in which member is defined
 * Public member can be accessed from everywhere; default
*/