factorial function (Scala)

	/**
	Typical example of a recursive function taught at school.
	But in practice implementing factorial recursively leads to a stackoverlow. And we can't use @tailrec for
	n! = n * (n-1)!
	BUT !! We don't really need recursion, do we?!
	**/
	package numbers
	object Numbers {
	/**
	1! = 1
	2! = 2 * 1! = 2 * 1 = 2
	3! = 3 * 2! = 3 * 2 = 6
	4! = 4 * 3! = 4 * 6 = 24
	5! = 5 * 4! = 5 * 24 = 120
	**/
	def factStackOverflow(num: Int): BigDecimal = {
	if (num == 1) 1
	else num * factStackOverflow(num-1)
	}
	/**
	1! = 1
	2! = 1! * 2 = 1 * 2 = 2
	3! = 2! * 3 = 2 * 3 = 6
	4! = 3! * 4 = 6 * 4 = 24
	5! = 4! * 5 = 24 * 5 = 120
	**/
	def factNonRecursive(num: Int): BigDecimal = {
	(1 to num).map(x => BigDecimal.valueOf(x)).foldLeft(BigDecimal.valueOf(1)) ((a,b) => (a * b))
	}
	}
	/**
	val x1 = Numbers.factNonRecursive(1) //> x1 : BigDecimal = 1.00
	val x2 = Numbers.factNonRecursive(10) //> x2 : BigDecimal = 3628800.00000000000
	val x3 = Numbers.factNonRecursive(10000) //> x3 : BigDecimal = 2.846259680917054518906413212119839E+35659
	val x4 = Numbers.factStackOverflow(1) //> x4 : BigDecimal = 1
	val x5 = Numbers.factStackOverflow(10) //> x5 : BigDecimal = 3628800
	val x6 = Numbers.factStackOverflow(10000) //> java.lang.StackOverflowError
	//| at java.math.MathContext.equals(Unknown Source)
	//| at scala.math.BigDecimal$.apply(BigDecimal.scala:61)
	//| at scala.math.BigDecimal$.apply(BigDecimal.scala:59)
	//| at scala.math.BigDecimal$.int2bigDecimal(BigDecimal.scala:146)
	//| Output exceeds cutoff limit.
	**/

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