Re: how to iterator and delete elements in std::set

From:

Michael Doubez <michael.doubez@free.fr>

Newsgroups:

comp.lang.c++

Date:

Thu, 25 Nov 2010 03:55:24 -0800 (PST)

Message-ID:

<8d07a896-61ae-4faa-a1b0-ecf47840e279@m20g2000prc.googlegroups.com>

On 25 nov, 10:55, sasoon <alexander.georg...@gmail.com> wrote:

On Nov 22, 1:12 am, zl2k <kdsfin...@gmail.com> wrote:

hi, there

std::set<Obj> objs;
...
for (auto obj_iterator = objs.begin(); obj_iterator != objs.end(); =

+obj_iterator){
    if (obj_iterator.do_you_want_to_be_erased() == true){
       objs.erase(*obj_iterator);
    }

}

Now I have the trouble since the iterator is destroyed after the first
erase. What is the proper way to do the job? Thanks.

I would use std::remove_if

http://www.sgi.com/tech/stl/remove_if.html

Would you ? Please, try it out before answering.

std::remove_if() copies the elements in the range such as removing the
unwanted value and returns the iterator to one past the last copied.

It doesn't work with std::set<> for two reason:
- the value are const and elements cannot be copied (in general)
- the internal structure is likely to be a RB-tree. copying the
values would make it a mess.

--
Michael