| Topic: |
DEVELOP > c-Plus-Plus |
| User: |
"lallous" |
| Date: |
13 Oct 2004 07:11:31 AM |
| Object: |
question about and pointer to its items |
Hello
Given this:
list<mystruct_t> lst;
lst.push_back(item1);
lst.push_back(item2);
lst.push_back(item3);
Now say I have this:
mystruct_t *p1, *p2, *p3 pointing to item1->item3 memory in side the list.
If I delete "item2" (or second item) will the other pointers still be valid?
--
Elias
.
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| User: "John Harrison" |
|
Title: Re: question about and pointer to its items |
13 Oct 2004 07:25:20 AM |
|
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"lallous" <lallous@lgwm.org> wrote in message
news:2t4kfoF1qsp5tU1@uni-berlin.de...
Hello
Given this:
list<mystruct_t> lst;
lst.push_back(item1);
lst.push_back(item2);
lst.push_back(item3);
Now say I have this:
mystruct_t *p1, *p2, *p3 pointing to item1->item3 memory in side the list.
If I delete "item2" (or second item) will the other pointers still be
valid?
If you use iterators instead of pointers (like you should) then the C++
standard guarantees that the iterators will remain valid. I don't know that
the standard guarantees that pointers will be OK, but its very likely to
work.
John
.
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| User: "Sharad Kala" |
|
Title: Re: question about and pointer to its items |
13 Oct 2004 07:44:14 AM |
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"John Harrison" <john_andronicus@hotmail.com> wrote in message
If you use iterators instead of pointers (like you should) then the C++
standard guarantees that the iterators will remain valid.
I think Standard only talks of iterators and references remaining valid, and
am too lazy to check the Standard :-)
Sharad
.
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| User: "lallous" |
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Title: Re: question about and pointer to its items |
13 Oct 2004 07:39:06 AM |
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"John Harrison" <john_andronicus@hotmail.com> wrote in message
news:2t4l39F1s60o6U1@uni-berlin.de...
"lallous" <lallous@lgwm.org> wrote in message
news:2t4kfoF1qsp5tU1@uni-berlin.de...
Hello
Given this:
list<mystruct_t> lst;
lst.push_back(item1);
lst.push_back(item2);
lst.push_back(item3);
Now say I have this:
mystruct_t *p1, *p2, *p3 pointing to item1->item3 memory in side the
list.
If I delete "item2" (or second item) will the other pointers still be
valid?
If you use iterators instead of pointers (like you should) then the C++
standard guarantees that the iterators will remain valid. I don't know
that
the standard guarantees that pointers will be OK, but its very likely to
work.
You mean I change p1, p2, p3 to:
list<mystruct_t>::iterator p1, p2, p3;
then have p1, p2, p3 point to each element, then when any element is deleted
the other iterators are still valid?
--
Elias
.
|
|
|
| User: "John Harrison" |
|
Title: Re: question about and pointer to its items |
13 Oct 2004 07:50:46 AM |
|
|
"lallous" <lallous@lgwm.org> wrote in message
news:2t4m3eF1qr7l2U1@uni-berlin.de...
"John Harrison" <john_andronicus@hotmail.com> wrote in message
news:2t4l39F1s60o6U1@uni-berlin.de...
"lallous" <lallous@lgwm.org> wrote in message
news:2t4kfoF1qsp5tU1@uni-berlin.de...
Hello
Given this:
list<mystruct_t> lst;
lst.push_back(item1);
lst.push_back(item2);
lst.push_back(item3);
Now say I have this:
mystruct_t *p1, *p2, *p3 pointing to item1->item3 memory in side the
list.
If I delete "item2" (or second item) will the other pointers still be
valid?
If you use iterators instead of pointers (like you should) then the C++
standard guarantees that the iterators will remain valid. I don't know
that
the standard guarantees that pointers will be OK, but its very likely to
work.
You mean I change p1, p2, p3 to:
list<mystruct_t>::iterator p1, p2, p3;
then have p1, p2, p3 point to each element, then when any element is
deleted
the other iterators are still valid?
Yes.
john
.
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