MESSAGE
| DATE | 2010-03-03 |
| FROM | Ruben Safir
|
| SUBJECT | Subject: [NYLXS - HANGOUT] C++ Workshop _ Syntax Basics - agregate data
|
From owner-hangout-outgoing-at-mrbrklyn.com Wed Mar 3 23:44:16 2010
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Date: Wed, 3 Mar 2010 23:45:10 -0500
From: Ruben Safir
To: hangout-at-nylxs.com
Subject: [NYLXS - HANGOUT] C++ Workshop _ Syntax Basics - agregate data
types
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On Wed, Mar 03, 2010 at 11:31:23PM -0500, Ruben Safir wrote:
> > string_ex.cc
> >
> > --------------------------------------------------
> >
> > #include
> > #include "test.h"
> > using namespace std;
> >
> > void stingexample(){
> >
> > char test[] = "My Dog has Fleas\n";
> > const char * test2 = "My Dog has Fleas\n";
> > cout << test;
> > test[3] = 'C';
> > test[4] = 'a';
> > test[5] = 't';
> > cout << test;
> > cout << test2;
> > const_cast(test2[3] = 'C');
> > const_cast(test2[4] = 'a');
> > const_cast(test2[5] = 't');
> > cout << test2;
> >
> > }
>
> I'd like to make a correction here as follows
>
> void stingexample(){
>
> char test[] = "My Dog has Fleas\n";
> const char * test2 = "My Dog has Fleas\n";
> cout << test;
> test[3] = 'C';
> test[4] = 'a';
> test[5] = 't';
> cout << test;
> cout << test2;
> const_cast(test2[3]) = 'C';
> const_cast(test2[4]) = 'a';
> const_cast(test2[5]) = 't';
> cout << test2;
>
> }
>
Incidentally, we can compile this substitution for string_ex.cc
--------------------------------------------------
#include
#include "test.h"
using namespace std;
void stringexample(){
char test[] = "My Dog has Fleas\n";
const char * test2 = "My Dog has Fleas\n";
char * test3;
cout << test;
test[3] = 'C';
test[4] = 'a';
test[5] = 't';
cout << test;
cout << test2;
test3 = const_cast(test2);
test3[3] = 'C';
test3[4] = 'a';
test3[5] = 't';
cout << test2;
}
---------------------------------------------
but it creates a segmentation fault on the line:
test3[3] = 'C';
if you add the compiler options -ggdb to your g++ commands in your
makefile, you can trace this error. This UNDERSCORES how dangerous that
explicit casting can be, even when allowed.
Ruben
--
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