Calling the copy contructor inside a method.

Question

Hello everyone, Ive got a pretty annoying delima right now. Im trying to write a method that uses the copy contructor inside it and it is simply put, just not working.
So how do you do this?
Example I have a copy contructor for a Dll that makes a new copy of a Dll. Now I want to write a method that when its called on a Dll object and given a Dll parameter as input it makes a copy of the input and saves it into the calling Dll object.
public void DLinkedList(DLinkedList theOriginal)  {
code
public void methodWithCopyContructorInside(DLinkedList list) {
DLinkedList newList = new DLinkedList(list);
????????? This is what I would consider to work but since im here you can guess its not.
Any suggestions, tips, comments would be most appreciated. Thank you.Message was edited by:
venture

Answer 1

Here is the code for the methods in question. I only didnt post all of it becuase it is alot of stuff and wasnt sure if anyone had the time and patience to read it. Sorry about that.
This is the Copy constructor.
public LinkedList( LinkedList theOriginal ) {
         if( theOriginal == this )
             ;// do nothing
              else {
             // old contents is detached. Deleted by garbage collector.
                  makeEmpty();
                  // Thread the original list inserting all the values found
                  // into the copy. This code is short but inefficient.
                  theOriginal.toHeadNode();
                  while( theOriginal.toNextNode() ) {
                 int coe = theOriginal.getCurrentCoefficient();
          int exp = theOriginal.getCurrentExponent();
                      insertInAscendingList(coe, exp);       
                         //insertInAscendingList( value );
This is the add method which is supposed to use the copy constructor inside it. Obvisouly from the name of my post you can conclude that this code is incorrect. But to me it seems correct. thus my dilemma.
public void add(LinkedList b) {
  LinkedList a = new LinkedList(b);
Here is the outputList method.
public void outputList()
    toHeadNode();
    while( toNextNode() ) // returns false if back at head
        System.out.print( curr.item + " " );
    System.out.println();
Now here is the driver program that uses these methods and constructors.
public static void main(String[] args)
    LinkedList a,b;
    a = new LinkedList();
    b = new LinkedList(a);
    b.outputList();  //This works
    //Now if I call the copy constructor everything works fine. A copy is made and method outputList() will print everything out perfect. But!!, Now if I use the add() method
   b.add(a);
   b.outputList(); //This doesnt work
im not sure what is being stored into b and outputList() returns nothing. A system.out.println() on b.add(a); returns LinkedList@d9f9c3 Message was edited by:
venture