[TriLUG] OT: C++ question, linked list of objects

[Barry Gaskins]

    You either need to change the declaration of the object class to make
next public.  Or you can add a public method sto the object to get and set
the value of next.

   - Barry Gaskins

On 4/2/06, Joseph Mack NA3T <jmack at wm7d.net> wrote:
>
> This is part of homework for a course I'm doing. I'm
> required to make a linked list of objects. I can do a linked
> list of structs, but when I do it with objects, object->next
> is private, which makes me think that I'm on the wrong
> track. Part of the homework is figuring out how to have a
> class as a node in a linked list.
>
> Google gives me stl libraries in template format, which I
> don't understand. I looked at newsgroups - it seemed to be
> either off-topic or I didn't understand it. All the webpages
> I've looked at have structs as the nodes in a linked list.
> (Why we have to figure this out ourselves, rather than being
> given some guidance in lectures and then go off and
> implement it is another matter.)
>
> I'm new at C++, can't do templates etc, so the explanation
> will have to be at a simple level.
>
> Here's the object class
>
> //Submarine.h
> class Submarine {
>
> private:
>     int num_engines;
>     //long list of private attributes
>     .
>     .
>     Submarine* next;
>
> public:
> };
>
>
> Here's the list class
>
> //List.h
> class List{
>
> private:
>     Submarine* head;
>     Submarine* tail;
>     int count; //number of submarines
>     ???
>
> What should go in the "???" so that I can do something like
>
> public:
>
>     void insert(const Submarine& submarine){
>        .
>        .
>        Submarine* current;
>        submarine.next = current; //problem: next is private,
>                                  //can use accessors but seems clunky
>        .
>     }
>
> }; //List class
>
> Am I supposed to use accessors or have I got the design
> completely wrong?
>
> Thanks Joe
>
> --
> Joseph Mack NA3T EME(B,D), FM05lw North Carolina
> jmack (at) wm7d (dot) net - azimuthal equidistant map
> generator at http://www.wm7d.net/azproj.shtml
> Homepage http://www.austintek.com/ It's GNU/Linux!
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