[LC++]Is there a place for public data members?

[Carlo Wood]

On Mon, Nov 05, 2001 at 06:48:54PM +1030, Mark Phillips wrote:
> Hi,
> 
> Instead of doing
> 
> class myClassTy {
> public:
>   int myInt;
> };
> 
> another approach is to do:
> 
> class myClassTy {
> private:
>   int myIntVt;
> public:
>   int myInt() const {return myIntVt;}
>   int& myInt() {return myIntVt;}
> };

The fact that myInt is public makes it that you can't
change myClassTy in a way that this integer changes
it's meaning.  The second approach has the same effect.
Both are "bad", and therefore I'd prefer the first
one for simplicity.

The following is a better approach,

class myClassTy {
private:
  int M_myInt;
public:
  int get_myInt(void) const { return M_myInt; }
  void set_myInt(int myInt) { M_myInt = myInt; }
};

You should think of class methods as "operators" that operate
on the object.  You should give them a name that reflects the
true meaning of the operator/method.

For example, if the `M_myInt' in the above reflects
the text color, then instead of giving direct access
to a variable `M_color' you'd rather define:

  Color get_text_color(void) const;
  void set_text_color(Color const&);

Assuming that the nature of the class defines `text'
clearly - then the meaning of this interface is safe
(even though you can later change what a 'Color' is).

-- 
Carlo Wood <carlo at alinoe.com>