Re: how to iterator and delete elements in std::set
On 11/21/2010 6:36 PM, Leigh Johnston wrote:
On 21/11/2010 23:12, zl2k wrote:
hi, there
Here is what I want to do: I have a set of objects. I need to iterate
each of them to ask if it needs to be eliminated. If yes, I'll erase
it from the set. I don't know which needs to be erased before I touch
it.
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.
zl2k
std::set<Obj> objs;
...
for (auto obj_iterator = objs.begin(); obj_iterator != objs.end();){
if (obj_iterator->do_you_want_to_be_erased())
objs.erase(obj_iterator++);
else
++obj_iterator;
}
To expand the answer:
In the new Standard all 'erase' members return the iterator immediately
following the one being erased or 'end()', so with the compliant
compiler you could write
if (obj_iterator->do_...
obj_iterator = objs.erase(obj_iterator);
else
++obj_iterator;
(not sure if it's better in any way, though). :-)
V
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