Getting null returned when working with Linked Lists

Question

Ok, i'm having the same problem with a couple of methods that deal with linked lists, and i was hoping someone could lend me a hand. First off, the specifications for one of the methods:
An iterative procedure smallElements
PARAMETERS: a ListItem reference, ls
an integer n
RETURN VALUE: a new list identical to the given list, except
that it contains no occurrences of numbers greater than n.
for example, given input list ( 3 2 6 3 4 ) and 3,
the return value would be the list ( 3 2 3 )
And here is my code:
ListItem smallElements(ListItem ls, int n){
ListItem small = null;
ListItem result = small;
if(ls == null)
return null;
else{
while(ls!=null){
     if(ls.number <=n){
     result = new ListItem(ls.number, null );
     result = result.next;
     ls = ls.next;
return small;
Like the topic says, i keep getting null returned as a value. I have tried setting small= new ListItem(ls.number, null), and that actually returns the correct list, except that the first number is repeated twice. I would greatly appreciate any assistance.

Answer 1

I am not sure I understand your code. What exactly are those ListItems? It seems to me that you are dealing with single List elements, while the specification says that you are supposed to return a List.
But the main error is that you have two ListItem objects there, which seems to fill the same purpose - only that you use one, and return the other. 'small', which is the one you return, never get set to anything else than null.
I think you should do something like this: make a new, empty list to return
for element in parameterlist
    if number is smaller than n
        add this element to returnlist
return returnlist