Re: Question about destructors

From:
Gus Gassmann <horand.gassmann@googlemail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 7 Feb 2012 09:13:37 -0800 (PST)
Message-ID:
<f7b07275-5374-4d4e-a679-44d9eb4cd719@eb6g2000vbb.googlegroups.com>
On Feb 7, 11:38 am, "Asger Joergensen" <J...@Asger-P.dk> wrote:

Hi Gus

Gus Gassmann wrote:

I have been working with C++ for about four years now, mostly self-
taught, and I get along reasonably well. However, last week I detected
a memory leak in some code, and trying to locate it I realized that I
do not know enough about destructors. I have created a number of use
cases. How can I make sure in each case that the memory gets destroyed
properly?


Freds solution is the best because it is exception safe, but the
golden rule is:

when ever You use the keyword new it should be matched with the
keyword delete
and when You use new [] it should be matched with delete[]

1. int *x[10];
nothing.

2. int *y = new int[10];
delete[] y;

3. Object *obj = new Object();
delete obj;

etc.

But again Freds solution is better, because the vector takes care of the
deletion when the vector runs out of scoop, even if there is an exception=

..

Some of the code is not written by me, so I am afraid Fred`s solution
does not work. Let me then summarize, just to be absolutely clear:

4. Object **obj = new Object[n];
   for (int i=0; i<n; i++) obj[i] = new Object();


     for (int i=0; i<n; i++) delete obj[i];
     delete[] obj;

5. Object *obj = new Object();
   obj->intArray = new int[10];


     delete[] obj->intArray;
     delete obj;

6. Object **obj = new Object[n];
   for (int i=0; i<n; i++) {
        obj[i] = new Object();
        obj[i]->intArray = new int[10];
   }


     for (int i=0; i<n; i++) {
         delete[] obj[i]->intArray;
         delete obj[i];
     }
     delete[] obj;

Will that do it? Thanks!

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