TITLE: accessors or public members

(Newsgroups: comp.lang.c++.moderated, 5 May 2000)


LEPINE: Guy Lepine <glepine@hydrosoftenergie.com>

> inline int GetA ()
> {
>     return A;
> }
>
> inline void SetA(int value)
> {
>     A = value;
> }
>
> Would it not be more efficient and faster (in terms of performance) to
> just let A be public and cut on the function call overhead? However, I
> know this is streching the encapsulation principle.

ALEXANDRESCU: "Andrei Alexandrescu" <andrewalex@hotmail.com>

I assume it's about member functions of a class.

I just said this in another post. Avoid public data like the plague,
even if conceptually you just need a get and a set. Access through
functions is much more flexible because you can later on:

* change from storing the data in a member variable to computing 
  it on the fly;
* validate data upon assignment;
* log assignments and trace that data's evolution;
* do actions that are triggered by that data's change;
* etc.

Exposing public data in a class makes your clients dependent not upon
a conceptual property of the object, but upon the physical
representation of that concept - as a member variable.


_______________________________________________
cpptips mailing list
http://cpptips.hyperformix.com