Why is it that wcout << “”; is OK but wcout << string(); is not?

Question

#include 
#include 

using namespace std;

int main()
{
    wcout << L\"Hello\";          // OK.
    wcout << wstring(L\"He         


        

Answer 1

For the first one, I'm guessing this overload is used:

template< class CharT, class Traits >
basic_ostream& operator<<( basic_ostream& os, 
                                         const char* s );

Where wstream is essentially a basic_ostream.

For why string("Hello") doesn't work, it's simply because there is no conversion from string to wstring, nor an overload of operator<< provided.