Factorial.kt

fun factorial(number: Int): Int {
    var factor = 1
    return if (number <= 1)
        factor
    else {
        (1 until number).forEach { factor*=(it+1) }
        factor
    }
}

fun factorialRec(number: Int): Int {

    return if (number<=1)
        1
    else number * factorialRec(number-1)

}
tailrec fun factorialTaiRec(number: Int, accumulator:Int):Int{
    return if (number==0)
        accumulator
    else factorialTaiRec(number-1,number*accumulator)
}