Re: Storing const references to other objects in another object.

From:

"Daniel T." <daniel_t@earthlink.net>

Newsgroups:

comp.lang.c++

Date:

Wed, 07 Apr 2010 08:43:55 -0400

Message-ID:

<daniel_t-548CC7.08435507042010@70-3-168-216.pools.spcsdns.net>

James Allsopp <jamesaallsopp@googlemail.com> wrote:

I have a list of item objects which I'm trying to find which of these
objects are close to each other. The data in these objects does not
change. I const::iterate though the vector these are stored in, and
where the condition is met, create a linker object in another class. I
don't want to recreate the classes, just store a reference to them.
The code from the linker is

class linker{
public:
        linker( const item &spectra, const item & core, double
distance):spectra(spectra),core(core),distance(distance){};
        const item & spectra;
        const item & core;
        double distance;
        int toString() const;

};

References were designed for argument passing, and it isn't appropriate
to use them as member-variables. Hold your items in const pointers
instead.

class linker {
   const item* _spectra;
   const item* _core;
   double _distance;
public:
   linker(const item& spectra, const item& core, double distance):
      _spectra(&spectra), _core(&core), _distance(distance)
   { }

   // default dtor, assignment and copy ctor do the right thing.

   const item& spectra() const { return _spectra; }
   const item& core() const { return _core; }
   double distance() const { return _distance; }
};