Re: Is a class a friend of itself?
Alan Woodland wrote:
Juha Nieminen wrote:
John wrote:
In the code below, if I define member functions that take an A object,
then I am able to change protected data members of the passed in A
object. Does this mean that all members functions of a class or friend
functions of the same class? This surprised me.
Why does it surprise you? Why shouldn't a class have access to its own
members?
If you wanted to restrict this, for whatever reason, exactly how would
you do that? You have no way of knowing whether a pointer is pointing to
the same object as 'this', other than actually making that check every
time a member is accessed, making every access slower. For what purpose?
I think this assumption comes from the 'Java Bean' way of thinking about
interfaces, data and objects. I've definitely seen this question a lot
from Java programmers. Which is odd because Java allows the exact same
thing...
I think some confuse access specifiers which are there to prevent errors
in programming, with "security attributes" which are usually aimed at
preventing malicious tempering, and sometimes (or often?) exist at the
object level instead of the class level.
V
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