won't compile, parse error?

[Christopher]

I am getting a parse error from g++ pointing at my catch line and can't
figure out whats wrong with this code:

#include "BigPosInt. h"
#include <iostream>
#include <new>
#include <assert.h>

BigPosInt::BigP osInt(int init_max_digits )
{
assert(init_max _digits > 0);

try
{
digitsArray = new int[init_max_digits];
}

catch(bad_alloc a)
{
const char* temp = a.what();
std::cout<<"\n\ n"<<temp<<"\ n";
std::cout<<"Ins ufficient free memory. \n\n";
}

// Postcondition: constructed BigPosInt has been initialized to
// represent the value 0 and can accommodate any
// BigPosInt that has up to init_max_digits digits
}

Any ideas?
thanx,
Christopher

[Alf P. Steinbach]

On Wed, 24 Sep 2003 04:17:17 GMT, "Christophe r" <cp***@austin.r r.com> wrote:

I am getting a parse error from g++ pointing at my catch line and can't
figure out whats wrong with this code:

#include "BigPosInt. h"
#include <iostream>
#include <new>
#include <assert.h>
Just to get into the habit try using <cassert> instead of <assert.h>.
Since 'assert' is a macro it's practically the same. But not for
other old C library headers.
BigPosInt::Big PosInt(int init_max_digits )
Here I would have used unsigned type for 'init_max_digit s'. However,
about 50% (as far as I can determine) of the community disagrees.
The 50% or so who agree think that 'unsigned' communicates the
"must be non-negative" requirement more clearly.

{
assert(init_max _digits > 0);
For 'unsigned' you'd want to make this 'assert( init_max_digits <= INT_MAX )',
just to be on the safe side.

try
{
digitsArray = new int[init_max_digits];
Assuming 'digitsArray' is a member variable.
}

catch(bad_alloc a)
Make that 'catch( std::bad_alloc const& a )'

{
const char* temp = a.what();
You don't need a temp variable here.

std::cout<<"\n\ n"<<temp<<"\ n";
std::cout<<"Ins ufficient free memory. \n\n";
Remember to rethrow the exception!

You'd probably also be better off flushing std::cout here.
std::cout << std::flush;
throw;
}

// Postcondition: constructed BigPosInt has been initialized to
// represent the value 0 and can accommodate any
// BigPosInt that has up to init_max_digits digits
If you don't rethrow the exception you will violate that
postcondition in case of an exception.
}

[Chris Johnson]

In article <hV************ ********@twiste r.austin.rr.com >, Christopher wrote:

I am getting a parse error from g++ pointing at my catch line and can't
figure out whats wrong with this code: I'm not one to be nit-picky but you might want to past the complete
diagnostic error next time.
#include "BigPosInt. h"
#include <iostream>
#include <new>
#include <assert.h>

BigPosInt::BigP osInt(int init_max_digits )
{
assert(init_max _digits > 0);

try
{
digitsArray = new int[init_max_digits];
}

catch(bad_alloc a) catch(std::bad_ alloc a)
// I see no using namespace std::bad_alloc
// or using namespace std; etc..
{
const char* temp = a.what();
std::cout<<"\n\ n"<<temp<<"\ n";
std::cout<<"Ins ufficient free memory. \n\n";
}

// Postcondition: constructed BigPosInt has been initialized to
// represent the value 0 and can accommodate any
// BigPosInt that has up to init_max_digits digits
}

Any ideas?
There's one for ya
thanx,
Christopher

Hope that helps,
Chris Johnson
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[Attila Feher]

Alf P. Steinbach wrote:
[SNIP]

BigPosInt::BigP osInt(int init_max_digits )
Here I would have used unsigned type for 'init_max_digit s'. However,
about 50% (as far as I can determine) of the community disagrees.
The 50% or so who agree think that 'unsigned' communicates the
"must be non-negative" requirement more clearly.

Most of the platforms don't agree with you. They cannot allocate or address
more bytes than the maximum of std::ptrdiff_t, and std::ptrdiff_t is signed.

std::cout<<"\n\ n"<<temp<<"\ n";
std::cout<<"Ins ufficient free memory. \n\n";

Remember to rethrow the exception!

You'd probably also be better off flushing std::cout here.

Why not simply use endl; above? Or better off cerr?
std::cout << std::flush;
throw;

Rethrowing is a good point.

--
Attila aka WW

[Attila Feher]

Christopher wrote:

I am getting a parse error from g++ pointing at my catch line and
can't figure out whats wrong with this code:

#include "BigPosInt. h"
#include <iostream>
#include <new>
#include <assert.h>

BigPosInt::BigP osInt(int init_max_digits )
{
assert(init_max _digits > 0);

try
{
digitsArray = new int[init_max_digits];
}

catch(bad_alloc a)

catch(std::bad_ alloc const &a)

--
Attila aka WW

[Chris Johnson]

In article <sl************ *********@gesta lt.localdomain> , Chris Johnson wrote:

In article <hV************ ********@twiste r.austin.rr.com >, Christopher wrote:
catch(std::bad_ alloc a)
// I see no using namespace std::bad_alloc
// or using namespace std; etc..

While I don't want to tear your code snippet apart
(you did ask a very specific question)
I want to correct something in my reply:

catch(std::bad_ alloc const& a)

I think in the end run this is more what you will be after
although my original post 'should' remove your parse error

Other points of mention are things like
#include <cassert>
instead of
#include <assert.h>
as well as other things - I'm not trying to "beat you up" though
I am sure more posters will correct some other parts of your
code, none of it with malicious intent of course.

Chris Johnson
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[Chris Johnson]

In article <bk**********@n ewstree.wise.ed t.ericsson.se>, Attila Feher wrote:

Christopher wrote:

catch(std::bad_ alloc const &a)

--
Attila aka WW

Yes yes - I noticed that immediately after I sent it and I am kicking
myself over that one. Unfortunately I couldn't delete the post before
it went out. I got in a hurry and didn't catch I was not finished with
my editing. Oh well nothing like leaving my mark in history on USENET
that I sometimes toggle the idiot bit and leave a public record of it.

D'OH!

Chris Johnson
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[Alf P. Steinbach]

On Wed, 24 Sep 2003 07:49:33 +0300, "Attila Feher" <at**********@l mf.ericsson.se> wrote:

Alf P. Steinbach wrote:
[SNIP]

BigPosInt::BigP osInt(int init_max_digits )
Here I would have used unsigned type for 'init_max_digit s'. However,
about 50% (as far as I can determine) of the community disagrees.
The 50% or so who agree think that 'unsigned' communicates the
"must be non-negative" requirement more clearly.

Most of the platforms don't agree with you. They cannot allocate or address
more bytes than the maximum of std::ptrdiff_t, and std::ptrdiff_t is signed.

Allocation error throws, too large or small range is not an issue here.

std::cout<<"\n\ n"<<temp<<"\ n";
std::cout<<"Ins ufficient free memory. \n\n";

Remember to rethrow the exception!

You'd probably also be better off flushing std::cout here.

Why not simply use endl; above? Or better off cerr?

Right. Even better, not do debug i/o at that level. I considered
how much to write about it, and I think I chose a good level to
further progress. Otherwise there's even more to say.

std::cout << std::flush;
throw;

Rethrowing is a good point.

All my points are good... ;-)

[Attila Feher]

Alf P. Steinbach wrote:

On Wed, 24 Sep 2003 07:49:33 +0300, "Attila Feher"
<at**********@l mf.ericsson.se> wrote:

Alf P. Steinbach wrote:
[SNIP]

BigPosInt::BigP osInt(int init_max_digits )

Here I would have used unsigned type for 'init_max_digit s'.
However, about 50% (as far as I can determine) of the community
disagrees. The 50% or so who agree think that 'unsigned'
communicates the "must be non-negative" requirement more clearly.
Most of the platforms don't agree with you. They cannot allocate or
address more bytes than the maximum of std::ptrdiff_t, and
std::ptrdiff_t is signed.

Allocation error throws, too large or small range is not an issue
here.

IMHO it is. If you give an interface saying: I can do 32 and in practice
portably you can only do 16 (and portably mean eg: Windows cannot) this is
not OK. Also according to Bjarne just to rule out negative numbers you must
not use unsigned. According to Dan Saks using std::size_t will lead to
problems, since most implementations will not support it.

And for you short, IMHO arrogant reply about it being a non-issue: if you
prefer runtime errors over compile time errors (khm: warnings) then I think
there is not much to discuss.

std::cout<<"\n\ n"<<temp<<"\ n";
std::cout<<"Ins ufficient free memory. \n\n";

Remember to rethrow the exception!

You'd probably also be better off flushing std::cout here.

Why not simply use endl; above? Or better off cerr?

Right. Even better, not do debug i/o at that level.

I see. So you prefer having a high level debug message saying "Something
went wrong somewhere"?
I considered how much to write about it,
and I think I chose a good level to
further progress. Otherwise there's even more to say.

Without knowing anything about the intent of the program snippet and its
context? What would those be?

std::cout << std::flush;
throw;

Rethrowing is a good point.

All my points are good... ;-)

Except of the unsigned. It makes the interface communicate a lie on most
platforms and in addition to this moves a compile time detectable bug to
runtime.

--
Attila aka WW

[Attila Feher]

Chris Johnson wrote:
[SNIP]

my editing. Oh well nothing like leaving my mark in history on USENET
that I sometimes toggle the idiot bit and leave a public record of it.

Been there, done that. More times than I care to admit. But this is the
way we learn. We make mistakes. At least mine does not start a war or a
blackout of a country. :-)

--
Attila aka WW