Why does string extraction from a stream set the eof bit?

Question

Let\'s say we have a stream containing simply:

hello

Note that there\'s no extra \\n at the end like there often is in a text

Answer 1

std::stringstream is a basic_istream and the operator>> of std::string "extracts" characters from it (as you found out).

27.7.2.1 Class template basic_istream

2 If rdbuf()->sbumpc() or rdbuf()->sgetc() returns traits::eof(), then the input function, except as explicitly noted otherwise, completes its actions and does setstate(eofbit), which may throw ios_- base::failure (27.5.5.4), before returning.

Also, "extracting" means calling these two functions.

3 Two groups of member function signatures share common properties: the formatted input functions (or extractors) and the unformatted input functions. Both groups of input functions are described as if they obtain (or extract) input characters by calling rdbuf()->sbumpc() or rdbuf()->sgetc(). They may use other public members of istream.

So eof must be set.