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C: Header Cell/Node in a Double Circularly Linkeded List

Discussion in 'C' started by Jose Francisco, Aug 23, 2007.

  1. Jose Francisco

    Jose Francisco New Member

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    Hey guys!

    I need some assistance in creating my header node or cell in a double circularly linked list. I have come up with the single linked list header node:

    Code:
    list_ptr createHeader (void){
     list_ptr L;
     L = (list_ptr) malloc(sizeof(list));
     L->next = NULL;
     return L;
    }
    However, I'm having difficulty in coding the header previous, which in fact would instantly point to the last node in my double circularly linked list. How do I go about adding that code to my createHeader function?

    Is it as simple as stating the following:
    Code:
    L->prev = NULL;
    Am I missing something?

    Thanks again!
    Regards,
    Jose :)
     
  2. shabbir

    shabbir Administrator Staff Member

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    It should be assigned when you have the second node in question or you can point to the head node itself whichever is useful to you. I would prefer assigning it to the head node.
     
  3. Jose Francisco

    Jose Francisco New Member

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    Hey shabbir!

    Thanks for the prompt reply. I am not really understanding your reply. How do we go about implementing that in my createHeader function?

    Do you meant it will be assigned automatically?

    Code:
    L->prev=L;
    Is that what you mean?

    Thank you for your time,
    Jose :)
     
  4. shabbir

    shabbir Administrator Staff Member

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    For the second node It will not be automatic but you need to be doing that but the second option I was saying is what you have understood.
     

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