Re: Const memebr function behaviour.

From:
Rolf Magnus <ramagnus@t-online.de>
Newsgroups:
comp.lang.c++
Date:
Fri, 18 May 2007 16:18:25 +0200
Message-ID:
<f2kcji$bko$00$2@news.t-online.com>
Rusty wrote:

Can somebody can explain the following behaviour. I have a small code
as below:

class B
{
   public:
       int b;
       B () { b = 0; };
       void foo2 (int h) { b = h; } // non-const function
};

class A
{
   public:
       int a;
       A () { cout << "Inside default constructor" << endl; b = new B
();}

       B* b;

       void bar () const { b->foo2 (3); } // problem. how can this
compile ?
};

void foo (const A* a)
{
   a->bar ();
}

int
main (int argc, char** argv)
{
   A a1;
   foo (&a1);
}

My concern is how could this code compile when in bar () function of
class A, I am calling non const function on pointer b ?


Why would that be a problem?

If instead of pointer, b is an object of type B, I get correct error
saying that inside const member function of class A, I cannot call non
const member function of B.


But you have a pointer. The constness of a pointer isn't related to the
constness of the object it points to.

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