Comments on: How to Delete Pointers in Vector or Map in Single Line?

By: A coder on break.

A coder on break. — Mon, 10 Aug 2009 15:42:14 +0000

[code]
// move template decl to the method itself.
class DeleteContainerElement
{
public:
template void operator()(T* pT){ delete pT; }
};

std::for_each( c.begin(), c.end(), DeleteContainerElement() );
[/code]

With this version you can delete container with raw pointers of any type.

By: Jijo.Raj

Jijo.Raj — Mon, 16 Mar 2009 11:39:01 +0000

Hi Pizer,

Thanks for going through my post and spend time to niggle out the problems.

>> The headers you

By: pizer

pizer — Sun, 15 Mar 2009 20:41:35 +0000

The headers you’ve included are all standard headers. The conventional way to include those is to use angle brackets.
You’re kind of suggesting that putting raw pointers in a container that need to be managed is OK. I beg to differ. That’s what smart pointers are for (i.e. tr1::shared_ptr) — It certainly doesn’t make much sense for string objects but that’s okay becuase it’s just an example.
The value_type of a map is pair but in your functor you take a pair by value which includes copying the key object. Since your functor is generic and the key class might be anything you should accept the map’s value by reference-to-const.

- P

By: Jijo.Raj

Jijo.Raj — Wed, 04 Mar 2009 03:53:49 +0000

Hi Torin,

Are you sure that you called the delete for each pointer before clearing the list? Or else it will surely leak. In the sample, operator() is calling delete. Well, as a fact MFC itself have a lot of leaks. It will be nice to inspect your code by using NuMega BoundsChecker or Rational Purify or by using some free memory detecting tool like this – http://www.codeproject.com/KB/debug/Memory_leak_finder.aspx

Regards,
Jijo.

By: Torin

Torin — Tue, 03 Mar 2009 10:43:49 +0000

I don’t know STL. I’m using C++ in general and MFC in specific.

I have problem about memory when deleting one/all/some element from a list/vector. Using the same declaration as above:
vector StringVector;

I have tried many different way to initialize the list, delete/clear items, but the memory usage of the whole program (as seen by Task Manager) keep increasing. The object(s) in the list are simply ‘de-linked’ but still remain in the memory.

I think your code above will suffer from the same issue. Any idea about this symptom?