STL List Erase

This is a discussion on STL List Erase within the C++ Programming forums, part of the General Programming Boards category; Hmm. I do not generally use the STL alot, but I have a large code base that uses STL list. ...

  1. #1
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    STL List Erase

    Hmm. I do not generally use the STL alot, but I have a large code base that uses STL list. I was growing fond of it until....erase. Is there a way to erase an element from the list without having the list structure specifically. All I want is to be able to write:

    Code:
    std::list<int> foo;
    foo.push_back(5);
    foo.push_back(6);
    
    std::list<int>::iterator bar;
    bar = foo.begin();
    bar++;
    then

    Code:
    bar.erase();
    or

    Code:
    erase(bar);
    or some such. I have looked through the stl code and I can't find the function so its either not there or I am looking in the wrong place. Thanks for the help

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  3. #3
    and the hat of sweating
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    I think you'd need to create a list that returns iterators that also contain a reference back to the list that they came from.

  4. #4
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by cpjust View Post
    I think you'd need to create a list that returns iterators that also contain a reference back to the list that they came from.
    You don't have to rewrite std::list, just make a new kind of iterator (based on the standard iterator).

  5. #5
    and the hat of sweating
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    Quote Originally Posted by brewbuck View Post
    You don't have to rewrite std::list, just make a new kind of iterator (based on the standard iterator).
    But how would you get std::list to return your custom iterator instead of its own?

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    Custom Iterator

    I am guessing as some have mentioned I would need a custom iterator. Obviously it can't be a member function of list (unless it is a static member, which I don't think there is). It needs to be a member function of the list::iterator class. If you look at the list::erase function it is very simple I suppose I could just copy the same thing into the iterator class.

  7. #7
    The larch
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    I'm afraid you shouldn't modify either std::list not std::list::iterator.

    You might be able to create your own free iterator that takes a reference to a std::list in its constructor so that it can provide the desired syntax for erase, but probably look ugly for anything else...

    Why do you have a problem with list.erase(iterator) in the first place?
    I might be wrong.

    Thank you, anon. You sure know how to recognize different types of trees from quite a long way away.
    Quoted more than 1000 times (I hope).

  8. #8
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    Sorry, I misread the question the first time.

    I would think that remembering which list the iterator belonged to should be state added to whatever code was handling that iterator.

    Creating a custom iterator or list seems like it would only make sense if you had (or expected to have) this problem in several unrelated areas of your application.

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