Re: [Boost-Users] Newbie boost::bind problem

12 Sep 2002

      From: "Mark Snelling" 
...
Hello,
I need some help using the boost::bind library. I have a map of objects
with a string as the key eg map, what I want to do is
call a member function on each Block* in the map using the std::for_each
algorithm. The trivial solution would be to craft my own loop and
iterate through the list calling the member function on each one. But
I'm sure that the boost::bind library can help me out there.
class Block
{
public:
     void update(int x);
};
void main()
{
     map blocks;
     for_each(blocks.begin(), blocks.end(), *****);
}
what should I replace the ***** with to call update() on each block?
std::for_each(blocks.begin(), blocks.end(),
        boost::bind(&Block::update,
            boost::bind(&std::map::value_type::second,
_1),
            5
        )
    );

if you insist. :-)

Another option:

template void for_each_pair(It first, It last, F f)
{
    for(; first != last; ++first)
    {
        f(first->first, first->second);
    }
}

int main()
{
    std::map blocks;
    for_each_pair(blocks.begin(), blocks.end(), boost::bind(&Block::update,
_2, 5));
}

Re: [Boost-Users] Newbie boost::bind problem

Peter Dimov