Re: adapter function for for_each

Greg Herlihy <>
Thu, 21 Aug 2008 07:28:35 CST
On Aug 20, 3:28 pm, dominolog <> wrote:

I've got following container:

std::vector<boost::shared_ptr<std::string> > strings;
strings.push_back( boost::shared_ptr<std::string> ( new
std::string("AAA") ) );


std::for_each( strings.begin(), strings.end(),
std::mem_fun( &std::length ) );

Now I want a 0-parameter method from std::string to be called on every
element from the sequence. '

The question is - how to construct a correct adapter for it, not using
a custom operand class. I want to use only stl stuff.

Use std::tr1::mem_fn(). For example:

     #include <tr1/memory>
     #include <tr1/functional>
     #include <string>
     #include <vector>
     #include <algorithm>

     using std::string;
     using std::tr1::shared_ptr;
     using std::tr1::mem_fn;

     int main()
         std::vector< shared_ptr<string> > v;

         std::for_each(v.begin(), v.end(), mem_fn(&string::length));


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