🚀 go-pugleaf

jlm@two-oo-one.fr wrote:
> 
> In C++ the "A::raz () const" doesn't change the content
> of an A, but it may change its behaviour. Let me take a
> simple example:
> 
> class A {
>     char* text_;
> public:
>     A (const char* t)
>         : text_ (strcpy (new char[strlen(t)+1], t)) {}
>     void raz () const {text_[0] = 0;}
> };

While it's true that the behavior of an A may change, all that
const means is that its content does not change -- which you 
appear to recognize.

The problem in this case is that you are using char* to mean 
"string", when all it really means is "pointer to char".  A 
better workaround, using the new standard (STL and ANSI string), 
is to say:

#include <bstring.h> // HP public-domain string implementation

class A {
    string text_;
public:
    A( const char* t ) : text_( t ) {}
    void raz() { text_[0] = 0; }
};

Note that raz() now cannot be const - making it const produces a 
compile-time error.


Allan

allan.drummond@trilogy.com
---
[ comp.std.c++ is moderated.  Submission address: std-c++@ncar.ucar.edu.
  Contact address: std-c++-request@ncar.ucar.edu.  The moderation policy
  is summarized in http://dogbert.lbl.gov/~matt/std-c++/policy.html. ]