initializing static stdlib containers

This is a discussion on initializing static stdlib containers within the C++ Programming forums, part of the General Programming Boards category; If I wanted to count how many objects of a class I make, I could write Code: // header.hh class ...

  1. #1
    Optics with a Twist skewray's Avatar
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    initializing static stdlib containers

    If I wanted to count how many objects of a class I make, I could write
    Code:
    // header.hh
    
    class bob
        {
        public:
            bob() ;
        private:
            static int bobCount_ ;
        }
    and then a file with the code and initialization

    Code:
    // code.cc
    
    #include "header.hh"
    
    bob::bobCount_ = 0 ;
    
    bob::bob()
        {
        bobCount_++ ;
        }
    So here is the question. Say I want to instead add each object to a stdlib set? Then my header file is

    Code:
    // header.hh
    
    #include <set>
    
    class bob
        {
        public:
            bob() ;
        private:
            static std::set<bob*> bobSet ;
        }
    and then a file with the code and initialization

    Code:
    // code.cc
    
    #include "header.hh"
    
    bob::bobSet = ????
    
    bob::bob()
        {
        bobSet.insert( this ) ;
        }
    So how do I initialize the set container class? The row of question marks doesn't work!

    Brian

  2. #2
    C++ Witch laserlight's Avatar
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    You can just write in code.cc:
    Code:
    std::set<bob*> bob::bobSet;
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
    Optics with a Twist skewray's Avatar
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    Thanks!

    Thanks, that definitely works. I never would have come up with the syntax, although now that I've seen it, I understand where it comes from.

    Brian

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