/*
* Yet another version of summing a list
* This one, instead of gettign the head and recurring on
* the rest of the list, does everything positionally.  Depending
* on the implementation of the list, this version may be much 
* faster, or must slower, than the other version
 */

fun main() {
    println(bb(listOf(1,2,3,4,5,6)))
}

/*
* Another list summer, this time using get to do a list element
* @param b3 -- a list of integers : default=null
* @param summ -- the number to consider to be the sum of an empty or null list: default 0
* @param pos -- the positionof the next item in the list to put into the
* sum : default=0
 */
tailrec fun bb(b3: List<Int>?=null, pos:Int=0, summ:Int=0) : Int {
    if (b3==null) return summ
    if (b3.isEmpty()) return summ
    if (pos<0) return summ
    if (pos >= b3.count()) return summ
    return bb(b3, pos+1, summ+b3.get(pos))
}