tellg（）和tellp（）在C ++中如何工作？

Question

Why do tellg() and tellp() always come together? And how can we separate them from each other?

Answer 1

They don't.

One indicates where the "get" cursor is in an input stream; the other indicates where the "put" cursor is in an output stream.

They are similar but not intrinsically linked, so the premise of your question is fundamentally flawed.

Answer 2

For starters, they're members of different classes: tellg is a member of std::istream , and tellp is a member of std::ostream . The reason they have different names is because there are classes (eg std::iostream ) which derive from both std::istream and std::ostream , and the functions may report different values: an actual std::streambuf type may maintain the read and write positions in sync (as does std::filebuf ) or keep them separate (as does std::stringbuf ).

Answer 3

One is for an input stream, the other for an output stream.

http://en.cppreference.com/w/cpp/io/basic_istream/tellg input stream position

http://en.cppreference.com/w/cpp/io/basic_ostream/tellp output stream position