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Hi,

I am using an iterator on a list, I wanted to know is there a simple
way to erase() the current element the iterator is pointing to and move
the iterator forward one?

The only way I can think of doing this is making a temp iterator equal
to orig position, then erasing, and setting the original iterator to
temp iterator++

Basically asking if there is a way to do the code below in two steps
instead of three.

Thanks,

RishiD

// move private iterator forward and eliminate person
void movingForward()
{
list<Person>::iterator tempIter = privIter;
circle.erase(privIter);
privIter = tempIter++;
}

RishiD wrote:
> I am using an iterator on a list, I wanted to know is there a simple
> way to erase() the current element the iterator is pointing to and
> move the iterator forward one?
> [..]

Is this a trick question? 'std::list::erase' has a return value
type, use it.

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

Victor Bazarov wrote:
> RishiD wrote:
> > I am using an iterator on a list, I wanted to know is there a simple
> > way to erase() the current element the iterator is pointing to and
> > move the iterator forward one?
> > [..]
>
> Is this a trick question? 'std::list::erase' has a return value
> type, use it.
>
> V
> --
> Please remove capital 'A's when replying by e-mail
> I do not respond to top-posted replies, please don't ask

Haha sorry. My professor told me otherwise, thanks.

Sorry for wasting your time.

In article < .com>,
"RishiD" <> wrote:

> Hi,
>
> I am using an iterator on a list, I wanted to know is there a simple
> way to erase() the current element the iterator is pointing to and move
> the iterator forward one?

Yes, simply call erase() and assign the return value to the iterator
object passed in.

> The only way I can think of doing this is making a temp iterator equal
> to orig position, then erasing, and setting the original iterator to
> temp iterator++
>
> Basically asking if there is a way to do the code below in two steps
> instead of three.
>
> Thanks,
>
> RishiD
>
> // move private iterator forward and eliminate person
> void movingForward()
> {
> list<Person>::iterator tempIter = privIter;
> circle.erase(privIter);
> privIter = tempIter++;
> }

void movingForward()
{
privIter = circle.erase( privIter );
}

or since you are working with a list, you could:

void movingForward()
{
circle.erase( privIter++ );
}

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Hi

Why not

circle.erase(privIter++);

privIter++ increments the iterator and returns the previous value
voila....

It would work even if the container didnt return an iterator from
erase()


Regards
Vivek

rep_movsd wrote:

> Hi
>
> Why not
>
> circle.erase(privIter++);
>
> privIter++ increments the iterator and returns the previous value
> voila....
>
> It would work even if the container didnt return an iterator from
> erase()

By container, you mean std::list: the idiom you propose does not work for
std::vector because of iterator invalidation. Using the return from erase()
provides the more robust code -- you could change the container to another
sequence type.


Best

Kai-Uwe Bux

"rep_movsd" <> wrote:

> Why not
>
> circle.erase(privIter++);

It's not as general purpose because it doesn't work for vector and may
not work for deque depending on where in the container the iterator is.

When you have a choice between a method that works for all Sequences and
one that only works for some Sequences, always choose the more general
approach unless you information that the specific method is faster.

> privIter++ increments the iterator and returns the previous value
> voila....
>
> It would work even if the container didnt return an iterator from
> erase()

All Sequences must return an iterator from erase, they don't all have to
keep the iterator valid.

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