I want to replace an object in a list with a new object....
std::list<myObj>::iterator it;
for (it=mylist.begin(); it != mylist.end(); ++it)
{
if (it->compair(myval) == 0)
{
*it = newval;
}
}
will *it = newval replace the contents of the list with the new
data... and hopefully delete the old object?
How do I insert and object just before the last element in the list?
7  2143 
SpreadTooThin <bj********@gmail.comwrote in
news:11**********************@d30g2000prg.googlegr oups.com:
I want to replace an object in a list with a new object....
std::list<myObj>::iterator it;
for (it=mylist.begin(); it != mylist.end(); ++it)
{
if (it->compair(myval) == 0)
{
*it = newval;
}
}
will *it = newval replace the contents of the list with the new
data... and hopefully delete the old object?
I don't see any dynamic allocation anywhere in here, so where's the
"delete" question coming from?
How do I insert and object just before the last element in the list?
Um:
if (!mylist.empty())
{
std::list<myObj>::iterator it = mylist.end();
--it;
mylist.insert(object, it);
}
else
{
// List is empty, there is no "last element" in the list
}
SpreadTooThin wrote:
I want to replace an object in a list with a new object....
std::list<myObj>::iterator it;
for (it=mylist.begin(); it != mylist.end(); ++it)
{
if (it->compair(myval) == 0)
{
*it = newval;
}
}
will *it = newval replace the contents of the list with the new
data... and hopefully delete the old object?
It will not "delete the old object". It will simply invoke
myObj::operator=(newval);
(assign new value) for it.
How do I insert and object just before the last element in the list?
There is an 'insert' member function (overloaded) in std::list. RTFM.
You will need to supply the iterator to the [actual] last item in the
list (don't confuse it with the iterator returned by 'list::end()').
V
--
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Andre Kostur wrote:
[..]
Um:
if (!mylist.empty())
{
std::list<myObj>::iterator it = mylist.end();
--it;
mylist.insert(object, it);
mylist.insert(it, object);
}
else
{
// List is empty, there is no "last element" in the list
}
V
--
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I do not respond to top-posted replies, please don't ask
"Victor Bazarov" <v.********@comAcast.netwrote in news:f4mrsh$6in$1
@news.datemas.de:
Andre Kostur wrote:
>[..]
Um:
if (!mylist.empty())
{
std::list<myObj>::iterator it = mylist.end();
--it;
mylist.insert(object, it);
mylist.insert(it, object);
Whups, yep. My bad.
>}
else
{
// List is empty, there is no "last element" in the list
}
On Jun 12, 1:20 pm, "Victor Bazarov" <v.Abaza...@comAcast.netwrote:
SpreadTooThin wrote:
I want to replace an object in a list with a new object....
std::list<myObj>::iterator it;
for (it=mylist.begin(); it != mylist.end(); ++it)
{
if (it->compair(myval) == 0)
{
*it = newval;
}
}
will *it = newval replace the contents of the list with the new
data... and hopefully delete the old object?
It will not "delete the old object". It will simply invoke
myObj::operator=(newval);
(assign new value) for it.
How do I insert and object just before the last element in the list?
There is an 'insert' member function (overloaded) in std::list. RTFM.
You will need to supply the iterator to the [actual] last item in the
list (don't confuse it with the iterator returned by 'list::end()').
After RTFM
I came up with mylist.insert(mylist.end(), 1, object);
No good?
V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask
SpreadTooThin <bj********@gmail.comwrote in news:1181679157.426254.202260
@g37g2000prf.googlegroups.com:
On Jun 12, 1:20 pm, "Victor Bazarov" <v.Abaza...@comAcast.netwrote:
>SpreadTooThin wrote:
I want to replace an object in a list with a new object....
std::list<myObj>::iterator it;
for (it=mylist.begin(); it != mylist.end(); ++it)
{
if (it->compair(myval) == 0)
{
*it = newval;
}
}
will *it = newval replace the contents of the list with the new
data... and hopefully delete the old object?
It will not "delete the old object". It will simply invoke
myObj::operator=(newval);
(assign new value) for it.
How do I insert and object just before the last element in the list?
There is an 'insert' member function (overloaded) in std::list. RTFM.
You will need to supply the iterator to the [actual] last item in the
list (don't confuse it with the iterator returned by 'list::end()').
After RTFM
I came up with mylist.insert(mylist.end(), 1, object);
No good?
No. As Victor warned you, you want an iterator to the last element in the
list, not the one-past-the-end element in the list. list<>::insert inserts
the element immediately before the element at the supplied iterator.
That's why in my example I had to back up one from the end() iterator (and
also why I had to check to ensure that the list wasn't empty to begin
with....).
SpreadTooThin wrote:
On Jun 12, 1:20 pm, "Victor Bazarov" <v.Abaza...@comAcast.netwrote:
>SpreadTooThin wrote:
>>I want to replace an object in a list with a new object....
>>std::list<myObj>::iterator it;
>>for (it=mylist.begin(); it != mylist.end(); ++it)
{
if (it->compair(myval) == 0)
{
*it = newval;
}
}
>>will *it = newval replace the contents of the list with the new
data... and hopefully delete the old object?
It will not "delete the old object". It will simply invoke
myObj::operator=(newval);
(assign new value) for it.
>>How do I insert and object just before the last element in the list?
There is an 'insert' member function (overloaded) in std::list.
RTFM. You will need to supply the iterator to the [actual] last item
in the list (don't confuse it with the iterator returned by
'list::end()').
After RTFM
I came up with mylist.insert(mylist.end(), 1, object);
No good?
You could drop the '1'. However, the effects of
mylist.insert(mylist.end(), object); // no '1', same difference
are the same as
mylist.push_back(object);
and it _appends_ the value to the list, not inserts it _before_ the
last element. See Andre's solution.
V
--
Please remove capital 'A's when replying by e-mail
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