Re: Const memebr function behaviour.

From:
=?iso-8859-1?q?Erik_Wikstr=F6m?= <eriwik@student.chalmers.se>
Newsgroups:
comp.lang.c++
Date:
18 May 2007 07:22:40 -0700
Message-ID:
<1179498160.891405.148060@k79g2000hse.googlegroups.com>
On 18 Maj, 16:15, Rusty <r_as...@yahoo.co.in> 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 ?

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.


If you have a B member and calls on the function that instance will be
const (since the function is const). However when you have a pointer
and call the function the *pointer* becomes const and not the object
it points to.

--
Erik Wikstr=F6m

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