Re: [Boost-users] A Problem with boost::bind

From: stevejay (stevemjohns2003_at_[hidden])
Date: 2006-05-05 11:28:37

Hi,

I get it (on VC++2003) as the problem being a lack of return_type typedefs.

Hossein Haeri wrote:
> 
> #include <iostream>
> #include <algorithm>
> #include <iterator>
> #include <vector>
> #include <boost/bind.hpp>
> #include <boost/mem_fn.hpp>
> 
> using std::ostream;
> using std::cin;
> using std::cout;
> using std::copy;
> using std::for_each;
> using std::ostream_iterator;
> using std::vector;
> using boost::bind;
> using boost::mem_fn;
> 
> template <class Container, size_t i>
> struct print
> {

        typedef ostream& result_type;

>   ostream& operator () (const Container& c, ostream&
> out) const
>   {
>     if(out)
>     {
>       typedef typename Container::value_type
> value_type;
>       typedef print<value_type, i - 1> NewPrint;
>       NewPrint newPrint;
>       /*      
>       for(typename Container::const_iterator j =
> c.begin(); j != c.end(); ++j)
>         newPrint(*j, out);
>       */
>       for_each(c.begin(), c.end(), bind(newPrint, _2,
> out)); //Error!
>     }  
>     return out;
>   }
> };
> 
> template <class Container>
> struct print<Container, 1>
> {

        typedef ostream& result_type;

>   ostream& operator () (const Container& c, ostream&
> out) const
>   {
>     if(out)
>       copy(c.begin(), 
>            c.end(),
>            ostream_iterator<typename
> Container::value_type>(out, " "));
>     return out;
>   }
>   ostream& DoIt (const Container& c, ostream& out)
> const
>   {
>     if(out)
>       copy(c.begin(), 
>            c.end(),
>            ostream_iterator<typename
> Container::value_type>(out, " "));
>     return out;
>   }
> };
> 
> int main()
> {
>   int a1[] = {1, 2, 3, 4};
>   const size_t n(sizeof(a1)/sizeof(*a1));
>   
>   vector<int> v(a1, a1 + n);
>   print<vector<int>, 1> () (v, cout);
> 
>   int a2[n] = {5, 6, 7, 8};
>   vector<vector<int> > m;
>   m.push_back(v);
>   m.push_back(vector<int>(a2, a2 + n));
>   print<vector<vector<int> >, 2> () (m, cout);
>   
>   cin.get();
>   return 0;
> }
> 

Bye,
Steve