Question

C++ delete of vector elements

Asked by: TruthHunter

Hi,

I have what I think is a very simple question, but since I need a quick definitive answer I'm giving it maximum points.

From C++ documentation II understand that when you have a vector of elements, and call the vector pop_back() or erase() methods, the destructor for the element(s) removed is supposed to be called automatically.  If the elements are pointers that were allocated via new(), then should delete() should be called for each element before it is removed from the vector?  Is the code below correct?  I'm chasing a memory leak/corruption and want to eliminate this possibility.  Thanks for any reply!

vector<CMyObj*>  vMyVec;
.
.
// allocate
CMyObj* pMyObj = new CMyObj();
vMyVec.push_back( pMyObj );
.
.
// cleanup
while (vMyVec.size() > 0)
{
    delete vMyVec[vMyVec.size() - 1];
    vMyVec.pop_back();
}

                                  
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Asked On
2009-08-26 at 07:54:02ID24683428
Tags

C++

,

memory

Topic

C++ Programming Language

Participating Experts
1
Points
500
Comments
4

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Answers

 

by: evilrixPosted on 2009-08-26 at 08:00:27ID: 25188415

>>  the destructor for the element(s) removed is supposed to be called automatically.
If the objects life ends (ie it goes out of scope) yes.

>> If the elements are pointers that were allocated via new(), then should delete()
Yes, heap allocated memory is your responsibility. You can avoid this by using a smart pinter such as the boost:shared_ptr. You CANNOT use std::auto_ptr though as it has move and not reference semantics so it is unsuitable for STL containers.

>> Is the code below correct?  
Only took a quick look but it should do what you expect, yes.

 

by: evilrixPosted on 2009-08-26 at 08:01:39ID: 25188431

 

by: TruthHunterPosted on 2009-08-26 at 09:06:08ID: 25189253

Thank you!

 

by: evilrixPosted on 2009-08-26 at 11:06:10ID: 25190471

You're very welcome.

20120131-EE-VQP-002

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