operator= problems

I am currently creating a circular linked class and I am having trouble with the operator= function. This is what I have.

Code:

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template <class Object>
const CircleList<Object> & CircleList<Object>::operator=(const CircleList & rhs)
{
  clear();
  CircleListItr<Object> ritr = rhs.returnBase();
  CircleListItr<Object> tempItr = rhs.returnBase();
  ++ritr;
 
  for ( ; ritr != tempItr; ++ritr)
      insert((*ritr).element);
     
  return *this;       
}

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Code:

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template <typename Object>
void CircleList<Object>::insert (const Object & x)
{
  CircleListNode<Object>* p = theBase;
  if (p->next == 0)
  {
          p->next = new CircleListNode<Object> ( x, p, p);
          theBase->previous = p->next;
  }
  else
  {
          while (p->next != theBase)
            {
            p = p->next;
            }
          p->next = new CircleListNode<Object> ( x, theBase, p);
          theBase->previous = p->next;
  }
}

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In the main function I have List 1 which is 3 8 6 5 9 2 1 .
So I create a List2, and do List2 = List1;

When I run the code, I determine through debugging it only runs through the while loop four times, inserting the first four items. It does not insert the 9 or anything after it and it terminates. Anyone know where I am going wrong?

Can't find the error yet, but you might want to check pointers for NULL rather than 0. Also, theBase isn't really defined anywhere. I assume it's a global pointer to the base...?

Also when you're iterating through the loop to find where you should insert the next node, you can simply create a pointer to theBase->previous and then do a new from there rather than iterating.

I also don't see code for setting the next pointer to theBase once you create a new node (after the iterations).

There might be more to it, but those are my observations from the posted code.

Quote:

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Originally Posted by brooksbp

but you might want to check pointers for NULL rather than 0.

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If you don't know that you said do this and don't do this as being the same thing, then try to refrain from offering it as advice.

Style advice bro... I and others would prefer reading code comparing pointers to NULL rather than 0 which could be quickly overlooked as an int esp if you haven't seen the variable name declared as a pointer... you don't have to carry over the mentality that 'users are dumb' to 'programmers are dumb'...

Point taken.
http://www.research.att.com/~bs/bs_faq2.html#null

>> Anyone know where I am going wrong?
I don't see anything wrong there. Can you post a simple main that exhibits the problem (make sure it outputs List1 before assigning it to List2). Also post the clear() function if possible.

This is my clear() function:

Code:

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Code:

       

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template <typename Object>
void CircleList<Object>::clear()
{
  CircleListNode<Object> *p = theBase;
 
  if ( p->next == 0 || p->next ==theBase)
    return;
 
  else
  {
          int size = sizeOfList();
          CircleListItr<Object> itr = returnBase();
    ++itr;
    for ( int i = 0; i < size; ++i)
           {
            removeWithIterator(itr);
            ++itr;
           }
         
  }
}

---

template <typename Object>
void CircleList<Object>::removeWithIterator (const CircleListItr<Object> & itr)
{
  CircleListNode<Object> *p = itr.current;
  p = p->previous;
 
  if ( p->next == 0)
    return;
 
  else
  {
  CircleListNode<Object> *tempNode = p->next;
  p->next = tempNode->next;
  tempNode->next->previous = p;
  delete tempNode;
  }
}

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I still don't see any real issues. Do you have access to a debugger? That would probably be really helpful.

Code:

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            removeWithIterator(itr);
            ++itr;

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Buggy (itr is invalid after a call to removeWithIterator), but wouldn't cause this problem.