Some questions in STL map and list using in c++

Hello I would like to ask about: I have map and list

Questions:

Is the following implementation of distructor right :

   for (map<string,SymbolTableNode*>::iterator i = symbolTable.begin();
                         i != symbolTable.end(); ++i)
   {
       delete i;
   }
   symbolTable.clear();

or I miss some memory?

About list:

   list<MyClass2*> mylist;
   mylist.push_front(new MyClass());
   mylist.pop_front();

does pop i开发者_开发知识库nvoke delete? or I have memory leakage in this case? If there is the leakage problem then what can I do to avoid it?

Thank you.

No pop_front won't invoke delete. You'll have to delete the pointer yourself before you pop it.:

list<MyClass2*> mylist;
mylist.push_front(new MyClass());
delete mylist.front();
mylist.pop_front();

And the destructor should probably be:

delete i->second;

you have a leak. See smart pointers (http://en.wikipedia.org/wiki/Smart_pointer)

More explicitely:

list<boost::shared_ptr<MyClass2> > mylist;


mylist.pop(); // now it will invoke delete

Do you really need to have a list of pointers ? Can't you have a plain list ?

list<MyClass> mylist;
mylist.push_front(MyClass());

It will save you the pain of memory management.

If you need pointers, then use smart pointers or pointer containers from boost : http://www.boost.org/doc/libs/1_46_1/libs/ptr_container/doc/ptr_container.html

delete i;

Wrong.

This should be this:

delete i->second; 

Because i points to a pair.

Nawaz - You are wrong.

Iterator element for a map is a pair so proper delete call is:

delete (*i).second;

P.S. Ok - now I see You have fixed this :)