List of lists

This is a discussion on List of lists within the C++ Programming forums, part of the General Programming Boards category; How would I access a list inside a list? Say for... Code: list<int> inside; list<list<int>* > outside; list<list<int> *>::iterator outIter; ...

  1. #1
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    Oct 2005
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    11

    List of lists

    How would I access a list inside a list? Say for...

    Code:
    list<int> inside;
    list<list<int>* > outside;
    list<list<int> *>::iterator outIter;
    list<int>:: iterator inIter;
    outside.push_front(&inside);
    outIter = outside.begin();
    
    inIter =   ???;

  2. #2
    Registered User
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    Jan 2005
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    7,317
    Is there a reason your inner list is a pointer? Why not just a list of lists?

    As is, you'd need to dereference the outIter iterator, which would give you a list pointer. Then you'd ned to dereference the list pointer and call the member function begin() to get an iterator pointing at the first int. So:
    Code:
    inIter = (*outIter)->begin();
    Of course, in the above code, you would never want to use inIter, because the inside list is empty.

    If you got rid of the pointer, it would look like this:
    Code:
    list<int> inside;
    list<list<int> > outside;
    list<list<int> >::iterator outIter;
    list<int>::iterator inIter;
    outside.push_front(inside); // note that a copy is pushed on to the list
    outIter = outside.begin();
    
    inIter = outIter->begin();

  3. #3
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    Oct 2005
    Posts
    11
    Thanks, was using pointer just becuase thats the way I had a vector of lists set up before. Just wanted to pick up the concept of how to work a list of list and wasn't sure how.

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