Re: Dynamic allocation of memory problem

From:

Victor Bazarov <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Thu, 18 Jun 2009 13:55:43 -0400

Message-ID:

<h1dv15$3ca$1@news.datemas.de>

Kazik? wrote:

Thank you Victor,
I know it sounds silly, but yes- I have calculated all "new"'s and
"delete"'s and the numbers match- both in dgeevCPP and in the part of
main() that I have pasted in the previous post. This is something that
makes me really crazy- it must work but it does not...
Talking about STL- I know I should learn them but since now I have to
finish the current project as soon as possible, it's not the most
effective idea to begin STL-education right now.
I suspect what could be the reason for running out of memory. It's
about the way that I initialize the 2-dimensional array, namely by the
function:

double** init_2_re(const int n){
  double **Matrix = new double*[n];
  for(int i=0; i<n; i++)
    Matrix[i] = new double[n];
  return Matrix;

}

So, in main() I write:
double** Matrix = init_2_re(2*Nz);
and when playing with Matrix is over:
delete [] Matrix;

That's your problem. How many 'new[]' do you have in the function
'init_2_re'? Count them properly. How many 'delete[]' do you have? One.

Ok, but then I thought: since I don't use word "new" (explicitly in
main()) to initialize the Matrix (though it appears in init_2_re),
maybe "delete [] Matrix" somehow doesn't work or work different then I
think? Is it possible?

No. All uses of 'new' have to be matched with 'delete' to avoid leaks
and all uses of 'new[]' have to be matched with 'delete[]'.

> I'm sorry if it's stupid but I'm really running

out reasonable ideas..

V
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