def functionName ([list of parameters]) : [return type] = {
   function body
   return [expr]
}
		

import scala.util.Random

object Demo
{
  // return an random integer
  def getNum() : Int = {
    var r = new Random();

    return r.nextInt(10);
  }

  // no return
  def hello() : Unit = {
    println("Hello World!");
  }

  def main(args : Array[String])
  {
    println(getNum());

    hello();
  }
}
		

object Demo
{
  def doSomething() : Int = {
    println("Do something ...");
    return 1;
  }

  // call by value
  def callByValue(x : Int) : Unit = {
    println(x);
    println(x);
  }

  // call by name
  def callByName(x : => Int) : Unit = {
    println(x);
    println(x);
  }

  def main(args : Array[String])
  {
    // pass an integer number, they have the same performance
    callByValue(10);
    callByName(10);

    //call by value
    println("Call by value ...");
    //>>Do something ...
    //>>1
    //>>1
    callByValue(doSomething());

    //call by name
    println("Call by name ...");
    //>>Do something ...
    //>>1
    //>>Do something ...
    //>>1
    callByName(doSomething());
  }
}
		

object Demo
{
  def getArgs(num : Int, args : String*)
  {
    println("Total %d parameters ...".format(num));

    for(arg <- args)
      println(arg)
  }

  def main(args: Array[String])
  {
    getArgs(4, "p1", "p2", "p3", "p4");
  }
}
		

object Demo
{
  def getSum(a : Int = 1, b : Int = 10) : Int = 
  {
    return a + b
  }

  def main(args : Array[String])
  {
    // not use default value
    println(getSum(1, 2));

    // pass value to a, b use the default value
    println(getSum(1));

    // a use the default value, assign value to b
    println(getSum(b=2));
  }
}
		

object Demo
{
  def factorial(i : Int) : Int = {
    def fact(i: Int, accumulator: Int): Int = {
         if (i <= 1)
            accumulator
         else
            fact(i - 1, i * accumulator)
      }
    return fact(i, 1)
  }

  def main(args : Array[String])
  {
    println(factorial(4));
  }
}
		

object Demo
{
  def getSum(a : Int, b : Int) : Int = {
    return a+b;
  }

  def main(args : Array[String])
  {
    var partialSum = getSum(1, _ : Int);

    println(partialSum(10));
  }
}
		

object Demo
{
  def getSum(a : Int = 1, b : Int = 2) : Int = {
    return a+b;
  }

  def main(args : Array[String])
  {
    println(getSum(b = 10, a = 100));
  }
}
		

object Demo
{
  def factorial(n : Int) : Int = {
    if( n <= 1)
      return 1
    else
      return n*factorial(n-1)
  }

  def main(args : Array[String])
  {
    println(factorial(4));
  }
}
		

object Demo {
   def main(args: Array[String]) {
      println( apply( layout, 10) )
   }

   def apply(f: Int => String, v: Int) = f(v)

   def layout[A](x: A) = "[" + x.toString() + "]" // A is parameter type
}
		

object Demo {
   def main(args: Array[String]) {
      println( apply(getSum, 10) )
   }

   def getSum(a : Int, b : Int) : Int = {
     return a+b;
   }

   def apply(f: (Int, Int) => Int, v: Int) = f(v, v)
}
		

object Demo
{
  def main(args : Array[String])
  {
    var getSum = (a:Int, b:Int) => a+b;

    println(getSum(10, 100));
  }
}
		

object Demo
{
  def doubleNum(a : Int) : Int = 2*a;

  def getSum(a: Int)(b : Int) : Int = {
    return doubleNum(a) + doubleNum(b)
  }

  def main(args : Array[String])
  {
    println(getSum(10)(100));
  }
}