iterator problem

Hi all,

I have a list of pointers to objects and I am trying to delete the objects before clearing the list. Here's the code:

.................................................. .............................................

1: for (iter = addrlist.begin(); iter != addrlist.end(); iter++)
2: {
3: delete iter;
4: }
5:
6: this->addrlist.clear();

.................................................. ...............................................

I tried de-referencing iter but it kept crapping out on line 3. In line 3, iter points to a cell in the list that holds a pointer to an object. I want to delete the object first, how do I do that? TIA


BTW, here's how I am populating the list:
.................................................. ................................................

1: Addresse* add = new Addresse();
2: add->setID(LastRecordId++);
3: this->addrlist.push_back(*add);

.................................................. ................................................

As you have a list of pointers to Addresse objects, then the iterator will be a pointer to a pointer to an Addresse object. So de-referencing iter before deleting should work.

Are you doing any memory management in your Addresse destructor?

Code:

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template <class container> void freeDynamicContainer(container& c) {
  for (typename container::iterator i = c.begin(); i != c.end(); i++) {
  delete (*i);
  }
  c.clear();
 }

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Quote:

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Originally posted by Sorensen

Are you doing any memory management in your Addresse destructor?

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Yes, I am trying to free memory in my destructor before exiting program.

Then if you were de-referencing iter, as per SilentStrikes example, and get the crash then it's likely that the error is in your destructor not your list deleting code.

...To add on to Sorensen's post,

you may be deleting the data twice.

p.s.

When the std::list goes out of scope, can you overload it's destructor (if it has one ??) so that it does the memory management ?

std::list (or any of the standard containers) doesn't have a virtual destructor... so you can't really do it. I was suprised g++ even let me compile this without warning (despite deriving from class with non-virtual destructor)

Code:

---

#include <list>
#include <iostream>

class check {
public:
 check() { count++;}
 ~check() {count--;}
 static int getCount() { return count; }
private:
 static int count;
};

int check::count=0;

template <class T> class ptrList: public std::list<T*> {
public:
 ptrList() { }
 ~ptrList() {
  for (std::list<T*>::iterator i = begin(); i != end(); i++) {
  delete *i;
  }
 }
};

int main() {
 std::list<check*>* blah = new ptrList<check>;
 blah->push_back(new check);
 blah->push_back(new check);
 delete blah;  // doesn't call ~ptrList() because of non-vrituality of ~std::list()
 std::cout << check::getCount() << std::endl; // would be 0 if they were deleted..
 return 0;
}

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