Re: exception on string (out_of_range)

From:
eric <cneric12lin0@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 7 Jul 2011 09:51:15 -0700 (PDT)
Message-ID:
<b164b46f-191b-49d2-9790-4e0b796b6f49@5g2000yqb.googlegroups.com>
On Jul 7, 9:36 am, eric <cneric12l...@gmail.com> wrote:

On Jul 7, 8:33 am, F=D6LDY Lajos <fo...@rmki.kfki.hu> wrote:

On Thu, 7 Jul 2011, eric wrote:

Dear Advanced C++ programers:

 from book (c++ cookbook), chapter 4, section 3: Storing Strings in=

 a

Sequence
---------
#include <iostream>
#include <vector>
#include <exception>

using namespace std;

int main() {

 char carr[] = {'a', 'b', 'c', 'd', 'e'};

 cout << carr[100000] << '\n'; // Whoops, who knows what's g=

oing

                                  /=

/ to happen

 vector<char> v;
 v.push_back('a');
 v.push_back('b');
 v.push_back('c');
 v.push_back('d');
 v.push_back('e');

 try {
    cout << v.at(10000) << '\n'; // at checks bounds and throw=

s

 } catch(out_of_range& e) { // out_of_range if it's inv=

alid

   cerr << e.what() << '\n';
 }
}
---------------------------------------------------------------------=

-

my g++ response
-----------------
eric@eric-laptop:~/cppcookbook/download$ g++ 4-7.cpp
4-7.cpp: In function ?int main()?:
4-7.cpp:20:11: error: expected type-specifier before ?out_of_range?
4-7.cpp:20:23: error: expected ?)? before ?&? token
4-7.cpp:20:23: error: expected ?{? before ?&? token
4-7.cpp:20:25: error: ?e? was not declared in this scope
4-7.cpp:20:26: error: expected ?;? before ?)? token
---------------------------------------------------------------------=

----------------

the code can be download from
http://examples.oreilly.com/9780596007614/
that mean it was tested success in some platform(vc++ in xp), so
please help, thanks a lot in advance, Eric


Try:

...
   } catch(exception& e) { // out_of_range if it's inva=

lid

...

regards,
Lajos


-------------------------------------------------------------------------=

--------------------------

Thanks both Lajos and Mike Doubez's suggestions , and it can compile
now by following your suggestion
but, it did not run as expected
-----------
eric@eric-laptop:~/cppcookbook/ch4$ g++ Example4-7.cpp
eric@eric-laptop:~/cppcookbook/ch4$ ./a.out
Segmentation fault
---------------------------------------------------------
Do you know why it didn't go through the catch of my program rather
than through compiler(or operationSystem)'s?
Thanks your help a lot in advance, Eric


I modify a little bit of original program to test where is that
"Segmentation fault" generate
-----------
#include <iostream>
#include <vector>
// #include <exception>
 #include <stdexcept>

using namespace std;

int main() {
  cout << "go throu 1 \n";
  char carr[] = {'a', 'b', 'c', 'd', 'e'};
  cout << "go throu 2 \n";
// cout << carr[100000] << '\n'; // Whoops, who knows what's going
                                   // to happen
  vector<char> v;
  v.push_back('a');
  v.push_back('b');
  v.push_back('c');
  v.push_back('d');
  v.push_back('e');
  cout << "go throu 3 \n";
  try {
  cout << carr[100000] << '\n';
    cout << "go throu 4 \n";
     cout << v.at(10000) << '\n'; // at checks bounds and throws
// } catch(out_of_range& e) { // out_of_range if it's invalid
     } catch(exception& e) {
/* I tried both above , they all produce same error */
    cerr << e.what() << " This is out of range\n";
  }
}
---------------------------------------------------------
my system response
-----------
../a.out
go throu 1
go throu 2
go throu 3
Segmentation fault
--------------------
why my catch cann't catch (cout << carr[100000] << '\n';)
's
out of range error?
Eric

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