Understanding Functions in Scala

	/**
	Functions are first class citizens in Scala and a function that takes a single argument
	obeys below interface (trait in scala). It should have a method called apply which takes
	an argument of type T1 and returns a value of type R.
	**/
	trait Function1[-T1, +R] extends AnyRef { self =>
	/** Apply the body of this function to the argument.
	* @return the result of function application.
	*/
	def apply(v1: T1): R
	}
	/**
	In Scala there are 2 ways to indicate that a class implements a function Trait:
	[1] extends Function1[Int,Int]
	[2] extends (Int => Int)
	You can also write a function using the def keyword
	**/
	object FuncFun {
	class DoubleFunction extends (Int => Int) {
	def apply(x:Int): Int = x * 2
	}
	def timesFour(x: Int): Int = x * 4
	def doSomethingWithNumber(x: Int, f: Int => Int): Int = f(x)
	def main(args: Array[String]): Unit = {
	//this will print 6
	println(doSomethingWithNumber(3, new DoubleFunction()))
	//this will print 8
	println(doSomethingWithNumber(2, timesFour))
	}
	}

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