Re: Deleting Vectors that Point to the Same Objects

From:
red floyd <redfloyd@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 5 Jan 2010 09:12:18 -0800 (PST)
Message-ID:
<a11d54f0-0547-4118-9bc5-ddff773d105f@t12g2000vbk.googlegroups.com>
On Jan 4, 10:32 pm, Rune Allnor <all...@tele.ntnu.no> wrote:

On 5 Jan, 06:55, Mike <westplas...@gmail.com> wrote:

Hello, I hope everybody had a good New Year.

I have a class that looks like the following:

class Foo {
public:
        Foo();
        ~Foo() {} // Destructor is defined.
...
private:
        std::vector<Bar*> _list1;
        std::vector<Bar*> _list2;
...

};

As my program runs, _list1 and _list2 are populated as follows:
Bar* bar = new Bar();
_list1.push_back(bar);
_list2.push_back(bar);

In general, _list2 is a subset of _list1, so it isn't redundant.

My question is, what do I need to put in the destructor of Foo to
correctly delete these vectors?


I'd have used boost::shared_pointer for these things.
The object is left alone if a pointer is deleted while
remaining pointers still refer to it, and destroyed only
when the last pointer to it is deleted.


I'd agree with Rune that you should use a shared_pointer, but if you
insist on naked pointers, since list2 is a subset of list 1, just
do the following in the destructor:

  for (std::vector<Bar*>::iterator it = _list1.begin();
       it != _list1.end();
       ++it)
         delete *it;

The destructor will then automatically destroy the vectors.

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