[comp.lang.c++] Data Hiding, private members, and globals

benson@odi.com (Benson I. Margulies) (07/05/89)

in 2.0:

class C1 {
   private:
	int x;
};

class C2 : private C1 {
   int y();
};

int x;

int C2::y ()
{
	return x;
}
 
takes an "attempt to reference private member X" error.

In other words, if I happen to pick a global name that matches an
inaccessible private member of my class, I get yelled at.  I consider
it sort of backwards to have to carefully check all the variable I
can't reference when choosing my names. It makes namespace pollution
prevention difficult, since as a purveyor of a base class I can't add
any private name without the risk of causing errors for my customers'
classes.


-- 
Benson I. Margulies

ark@alice.UUCP (Andrew Koenig) (07/05/89)

In article <391@odi.ODI.COM>, benson@odi.com (Benson I. Margulies) writes:

> In other words, if I happen to pick a global name that matches an
> inaccessible private member of my class, I get yelled at.

Yes, but at least it's only inside member functions.

The compensating advantage is that if a C++ program compiles,
its semantics will remain the same even if you change all private
data and derivations to public.

Moreover, if you want to insist on referring to global data,
you can always put a :: in front of the name to make your intentions clear.
-- 
				--Andrew Koenig
				  ark@europa.att.com