Re: Deriving from STL containers

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Thu, 31 May 2007 10:56:08 -0400

Message-ID:

<f3mnm9$2er$1@news.datemas.de>

Adrian wrote:

Lint (rightly I believe) complains that deque's destructor is not
virtual. So will the following code cause any problems?

No.

If I do not derive from Container does that stop problems?

What problems?

Do I manually have to call deque's destructor from Containers to make
sure?

Absolutely not.

Adrian

#include <stdexcept>
#include <deque>

class SomeClass
{

};

typedef std::deque<SomeClass *> list_t;
class Container : private list_t
{
public:
Container() {};
using list_t::pop_front;

It is possible that you're going to leak memory if you allow
pop_front without deleting the element.

   using list_t::front;
   using list_t::empty;
   using list_t::size;
   void clear()
   {
     for(const_iterator i=begin(); i!=end(); ++i)
     {
       delete (*i);
     }
     list_t::clear();
   };
   void push_back(SomeClass * const obj)
   {
     if(size()>10)
     {
       throw std::runtime_error("much to big");
     }
     list_t::push_back(obj);
   };

   ~Container()
   {
     clear();
   }
private:
   Container(const Container &);
   Container &operator=(const Container &);
};

int main(int argc, char *argv[])

If you don't use 'argc' and 'argv', don't declare them.

{
Container container;

for(int i=0; i<9; ++i)
{
container.push_back(new SomeClass());
}

return 0;
}

V
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