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Andreas
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 Posted: Tue Dec 13, 2005 6:09 pm Post subject: Removing items from a list without deleting the item itself? |
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Hi there,
assume I have a number of structure elements filled with some dummy
values...
struct ListElement_st
{ int foo1;
int foo2;
};
ListElement_st ListElement[4];
for(int i=0;i<4;i++)
{ ListElement[i].foo1=i;
ListElement[i].foo2=-i;
}
....and I add these ListElements to a list class object (I am talking
std::list):
list
for (int l=0;l<4;l++)
LinkedList.push_back(ListElement[l]);
As far as I understand, the list class object creates a copy of the
structures passed through push_back(<...>) for the _Myval value in the
_Pnode structure.
Is it possible to remove an element from the list without deleting the
element (structure) itself? I would like to get rid of the element in
the list, but keep an pointer to the element (_Myval) for further
processing without creating another copy.
As far as I had a look in the <list> code, the erase function destroys
both, the link (prev/next) information as well as the payload (_Myval).
I would like to avoid working with a list of pointers as this adds
another level of indirection.
Any idea on how to do this?
Merry Christmas and a Happy New Year!
Cheers,
Andreas
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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Carl Barron
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| Posted: Wed Dec 14, 2005 6:13 am Post subject: Re: Removing items from a list without deleting the item its |
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In article <1134465213.715434.181990 (AT) o13g2000cwo (DOT) googlegroups.com>,
Andreas <dg6gai (AT) gmail (DOT) com> wrote:
| Quote: | Hi there,
assume I have a number of structure elements filled with some dummy
values...
struct ListElement_st
{ int foo1;
int foo2;
};
ListElement_st ListElement[4];
for(int i=0;i<4;i++)
{ ListElement[i].foo1=i;
ListElement[i].foo2=-i;
}
...and I add these ListElements to a list class object (I am talking
std::list):
list
for (int l=0;l<4;l++)
LinkedList.push_back(ListElement[l]);
As far as I understand, the list class object creates a copy of the
structures passed through push_back(<...>) for the _Myval value in the
_Pnode structure.
Is it possible to remove an element from the list without deleting the
element (structure) itself? I would like to get rid of the element in
the list, but keep an pointer to the element (_Myval) for further
processing without creating another copy.
As far as I had a look in the <list> code, the erase function destroys
both, the link (prev/next) information as well as the payload (_Myval).
I would like to avoid working with a list of pointers as this adds
another level of indirection.
Any idea on how to do this?
use list<T,A>::splice |
list<ListElement_st> HoldRemovedItems;
// move one item from LinkedList to HoldRemoved Items
// if it points to the item in LinkedList, It will point to the
// same item in HoldRemovedItems.
HoldRemoveItems.splice(HoldRemovedItems.end(),LinkedList,it);
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]
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