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Problem with STL map iterators

Started by Hazelnuss May 28, 2003 at 10:50 AM 9 replies 450+ views

Original Post

May 28, 2003 at 10:50 AM

Does anybody have an idea why i can't do this?

        
void CResourceManager::ReleaseAll()
{
	std::map<int, int>::iterator iter;
	for(iter = m_References.begin(); iter != m_References.end(); ++iter)
	{
		while(iter.second)
			Release(iter.first);
	}
}

The compiler says that "second" is not an element of

'_Rb_tree_iterator,struct _STL::_Nonconst_traits > >'

I am using STLPort. Thanks for any help. [edited by - Hazelnuss on May 28, 2003 11:51:45 AM] [edited by - Hazelnuss on May 28, 2003 11:52:17 AM] [edited by - Hazelnuss on May 28, 2003 11:52:47 AM]

pag

May 28, 2003 at 10:55 AM


i dont use stl, so my ideas can be crap... 
anyways, perhaps the second and first are methods? not variables?

kuphryn

May 28, 2003 at 11:01 AM

Use a temporary variable to hold the map''s key and/or value.

int nTemp = iter.second;

Kuphryn

Qw3r7yU10p!

May 28, 2003 at 11:05 AM

The iterator doesn't have those as members. The thing the iterator is pointing to does.

You need to derefernce the iterator first to get the std:: pair which has first and second as members.

(*iter).first;

[edited by - petewood on May 28, 2003 12:06:22 PM]

darookie

May 28, 2003 at 11:08 AM

quote:
Original post by pag

i dont use stl, so my ideas can be crap...

Agreed

JK

Solution. iterator are classes and you must use the dereference
operator to access their content like this:

    
void CResourceManager::ReleaseAll()
{	
     std::map<int, int>::iterator iter, end; // avoid redundant calls


     for(iter = m_References.begin(), end = m_References.end(); iter != end; ++iter)
     {
       int temp = iter->second;    // method 1)

       while(temp--)               // watch out for infinitive loops!

	  Release((*iter).first);  // method 2)

     }
}

[edit]
Seems I was a little too slow

[/edit]

[edited by - darookie on May 28, 2003 12:09:03 PM]

darookie

May 28, 2003 at 11:16 AM

Hazelnuss: I just noticed that you try to release the same resource multiple times - is this really what you intended
to do?

Another thing, after ReleaseAll() you should also clear the reference map:

   
   m_References.clear();

Hazelnuss

May 28, 2003 at 12:09 PM

Thanks for your answers thus far! I am gonna try them out.

quote:
Original post by darookie
Hazelnuss: I just noticed that you try to release the same resource multiple times - is this really what you intended
to do?

Another thing, after ReleaseAll() you should also clear the reference map:

Yep, that's what i want. I am working with reference counters and each Release() decrements it. When it is equal 0 the resource is deleted from memory. And i am calling ::clear() in the destructor because i might want to reload the resources after calling ReleaseAll().

[edited by - Hazelnuss on May 28, 2003 1:10:13 PM]