elements in std::set

This is a discussion on elements in std::set within the C++ Programming forums, part of the General Programming Boards category; Hello I have a simple Code: std::set<object> someset; Where object is: Code: class object { public: void some_function() { } ...

  1. #1
    l2u
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    elements in std::set

    Hello

    I have a simple
    Code:
    std::set<object> someset;
    Where object is:

    Code:
    class object {
    public:
      void some_function() { }
    };
    How can I call some_function() for all elements in set container with STD algorithms within one line?

    Many thanks in advance!

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    Code:
    std::for_each( someset.begin(), someset.end(),
                   boost::bind( &someset::some_function, _1 ) );

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    l2u
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    Thanks a lot!

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    Registered User hk_mp5kpdw's Avatar
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    FYI, the non-boost way (I believe?) would be:
    Code:
    std::for_each(someset.begin(),someset.end(),std::mem_fun_ref(&object::some_function));
    I could be a little off there...

    Quote Originally Posted by pheres
    Code:
    std::for_each( someset.begin(), someset.end(),
                   boost::bind( &someset::some_function, _1 ) );
    I've never used boost before, but are you sure that's right? someset is a set container so does &someset::some_function make sense if some_function is a member function of object? It just looks a little off.
    Last edited by hk_mp5kpdw; 10-08-2008 at 06:21 AM.
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    -Christopher Hitchens

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    ups, you are right:

    Code:
    std::for_each( someset.begin(), someset.end(),
                   boost::bind( &object::some_function, _1 ) );
    does it work?

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    use mem_fun or mem_fun_ref with for_each:
    Code:
    for_each(container.begin(), container.end(), mem_fun_ref( &object::some_function )  )
    It is too clear and so it is hard to see.
    A dunce once searched for fire with a lighted lantern.
    Had he known what fire was,
    He could have cooked his rice much sooner.

  8. #8
    l2u
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    Quote Originally Posted by King Mir View Post
    use mem_fun or mem_fun_ref with for_each:
    Code:
    for_each(container.begin(), container.end(), mem_fun_ref( &object::some_function )  )
    Can you pass function arguments with mem_fun ?

  9. #9
    Registered User hk_mp5kpdw's Avatar
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    Let's say that some_function was a member function that accepted an integer as an argument... you could then do (as an example):
    Code:
    std::for_each(someset.begin(),someset.end(),std::bind2nd(std::mem_fun_ref(&object::some_function),4));
    Which would effectively call the member function some_function(4) for each object in container someset... if I understand what you're asking.
    "Owners of dogs will have noticed that, if you provide them with food and water and shelter and affection, they will think you are god. Whereas owners of cats are compelled to realize that, if you provide them with food and water and shelter and affection, they draw the conclusion that they are gods."
    -Christopher Hitchens

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