How to convert wstring into string?

As Cubbi pointed out in one of the comments, std::wstring_convert (C++11) provides a neat simple solution (you need to #include <locale> and <codecvt>):

std::wstring string_to_convert;

//setup converter
using convert_type = std::codecvt_utf8<wchar_t>;
std::wstring_convert<convert_type, wchar_t> converter;

//use converter (.to_bytes: wstr->str, .from_bytes: str->wstr)
std::string converted_str = converter.to_bytes( string_to_convert );

I was using a combination of wcstombs and tedious allocation/deallocation of memory before I came across this.

http://en.cppreference.com/w/cpp/locale/wstring_convert

update(2013.11.28)

One liners can be stated as so (Thank you Guss for your comment):

std::wstring str = std::wstring_convert<std::codecvt_utf8<wchar_t>>().from_bytes("some string");

Wrapper functions can be stated as so: (Thank you ArmanSchwarz for your comment)

std::wstring s2ws(const std::string& str)
{
    using convert_typeX = std::codecvt_utf8<wchar_t>;
    std::wstring_convert<convert_typeX, wchar_t> converterX;

    return converterX.from_bytes(str);
}

std::string ws2s(const std::wstring& wstr)
{
    using convert_typeX = std::codecvt_utf8<wchar_t>;
    std::wstring_convert<convert_typeX, wchar_t> converterX;

    return converterX.to_bytes(wstr);
}

Note: there’s some controversy on whether string/wstring should be passed in to functions as references or as literals (due to C++11 and compiler updates). I’ll leave the decision to the person implementing, but it’s worth knowing.

Note: I’m using std::codecvt_utf8 in the above code, but if you’re not using UTF-8 you’ll need to change that to the appropriate encoding you’re using:

http://en.cppreference.com/w/cpp/header/codecvt