Question

ok so i wrote a program which scaans all directories an sub directories to find sepcific file extensions(i pass a string for the extension type i want) then it returns a vector loade with all the filenames with the specific filetype extensions. then i have another class which has a function that print out all of the files in the vector and will then will iterate the vector and run a program in that vector that the user chooses. This is my problem. Getting the file from the vvector to run. i am using visual studios on windows 7
using boost filesystem V3. this is my current function:

#define BOOST_FILESYSTEM_NO_DEPRECATED

#ifndef NotePad__h
#define NotePad__h

#include boost/filesystem.hpp
#include iostream
#include io.h
#include stdlib.h
#include stdio.h
#include cstdlib
#include Windows.h
#include atlstr.h
#include string
#include cstring
;
namespace fs = boost::filesystem;

class NpLaunch 
{
public:
    void Launch (const std::vector<fs::path>& v)
    {
        int count=0;
        std::cout << "launched in notePad.h" << std::endl;
        for(auto i = v.begin(); i!= v.end(); ++i)
        {
            //string s;
            //string val = (string) itr;
            std::cout << count << ". " << *i << std::endl;
            ++count;
            std::string s = i->c_str();
            //std::system(i->c_str());
        }
    }

};

#endif

and this is the error im getting:

Error 1 error C2440: ‘initializing’ : cannot convert from ‘const >boost::filesystem3::path::value_type *’ to ‘std::basic_string<_Elem,_Traits,_Ax>’ >c:\users\admin\documents\visual studio 2010\projects\launcher\launcher\notepad.h 31

Answer 1

On Windows, path::value_type is a wchar_t, and thus path::string_type is equivilent to std::wstring, and the path::c_str() method returns a wchar_t*. You cannot assign a wchar_t* to a std::string, that is what the compiler error is trying to tell you.

To assign a path object to a std::string, you have to perform a character conversion from wchar_t to char. The path::string() method does that for you, eg:

std::string s = i->string(); 

Otherwise, use a std::wstring instead, which you can assign to using either the path::native() or path::wstring() method, eg:

std::wstring s = i->native(); 

std::wstring s = i->wstring();