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i have gone through both the list iterator
m_iter_item & Iter_item from begin to end.
using _ptr->_Next and _ptr->_Prev
addresses in both the iterators are identical.

i have no clue why ++*this is crashing.

code in the above case is:
-----------------------------------------
1> class dummy
2> {
3> ..
4> ..
5> private:
6> list<mItem>::iterator m_iter_item;
7> }
8>
9> void dummy::func1()
10> {
11> list<mItem>::iterator iter_item;
12> getItem(&iter_item);
13> m_iter_item = iter_item;
14> ..
15> m_iter_item++;
16> ...
17> }
-----------------------------------------
when i changed the function func1() as

9> void dummy::func1()
10> {
11> list<mItem>::iterator iter_item;
12> getItem(&m_iter_item);
13> ..
14> m_iter_item++;
15> ...
16> }

there is no problem at all.

regards,
srinivas



Daniel T. wrote:
> "srinivas" <> wrote:
> >
> > is assignment of an iterator to another iterator valid?
> > i have found this assignment is creating problem.
> >
> > m_iter_item = iter_item;
> > m_iter_item++;
>
> Assignment from one object to another of the same type is valid if the
> class was written such that it is valid. The above code does not compile
> on its own (which does create a problem.
>
> You probably need to provide a valid op=.

dear daniel,
"++*this" is in the C++ STL library, i did not write it.

srinivas

Daniel T. wrote:
> "srinivas" <> wrote:
>
> > i am incrementing a list iterator "m_item" in my .cpp file
> >
> > > m_item++
> >
> > m_item._ptr->_next is showing the valid item.
> >
> > but in the library overloaded function for ++
> >
> > 1 >_Myt_iter operator++(int)
> > 2 > { // postincrement
> > 3 > _Myt_iter _Tmp = *this;
> > 4 > ++*this;
> > 5 > return (_Tmp);
> > 6 > }
> >
> > (line 4)++*this is crashing...it is not showing any item in its next
> > pointer.
> >
> > what is the problem?
>
> Line 4 should be: ++(*this);

Daniel T. wrote:
> "srinivas" <> wrote:
>
>> i am incrementing a list iterator "m_item" in my .cpp file
>>
>>> m_item++
>> m_item._ptr->_next is showing the valid item.
>>
>> but in the library overloaded function for ++
>>
>> 1 >_Myt_iter operator++(int)
>> 2 > { // postincrement
>> 3 > _Myt_iter _Tmp = *this;
>> 4 > ++*this;
>> 5 > return (_Tmp);
>> 6 > }
>>
>> (line 4)++*this is crashing...it is not showing any item in its next
>> pointer.
>>
>> what is the problem?
>
> Line 4 should be: ++(*this);

Why?

(hint: there is no difference between ++(*this) and ++*this).

--
Clark S. Cox III

srinivas wrote:
> i have gone through both the list iterator
> m_iter_item & Iter_item from begin to end.
> using _ptr->_Next and _ptr->_Prev
> addresses in both the iterators are identical.
>
> i have no clue why ++*this is crashing.
>
> --snip--

Perhaps you are removing items from the list (or adding to it ) ?
Is your iterator still valid ( the value in it pointed in list was
changed or even removed ? )

Or the iterator was already pointing to wrong location ( at or after
list.end() )

I suppose the iterator is normal forward iterator, not reverse_iterator.

Or you have memory corruption, you are overwriting the iterator fields
somehow.

ismo

srinivas wrote:

> hi Ondra
> thanks for reply.

Please don't top-post. Your replies belong following or interspersed
with properly trimmed quotes. See the majority of other posts in the
newsgroup, or the group FAQ list:
<http://www.parashift.com/c++-faq-lite/how-to-post.html>