Re: Problem with pointers and iterators

[Victor Bazarov]

Griff Johns wrote:

Hi, if I have the following code:
class MyObject
{
public:
MyObject() {};
~MyObject() {};
>
int x;
>
}
>
class MyObjectList : public std::vector<MyO bject{};
>
void Foo(MyObject* obj)
{
// Do something with obj->x
>
}
>
If I loop through it like this:
>
MyObjectList list;
// stuff list with objects
>
MyObjectList::i terator it;
for (it = list.begin(); it != list.end(); ++it) {
// I used to be able to do this:
MyObject* p_obj = it;
Foo(p_obj);
>
// Or this
Foo(it);
>
}
>
But now the error I get is 'cannot convert parameter 1 from
'std::vector<_T y>::iterator' to 'MyObject *'
>
This is after migrating a project from vc6.0 to vc7.1, but I think that
the issue lies with the language standards(?). So why does this happen
now, and how do I resolve it?

You need to *fix it*. Iterators are *not* pointers. If you need to
gain access to the address of the object to which the iterator points,
you need to dereference the iterator and then take the address of the
result:

MyObject *p_obj = &*it;

or

Foo(&*it);

Dereferencing yields a reference, taking the address of a reference
yields a pointer.

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask