>>57

http://www.lysator.liu.se/c/c-faq/c-11.html#11-12
> 11.12: How can I flush pending input so that a user's typeahead isn't read at the next prompt? Will fflush(stdin) work?
>fflush is defined only for output streams. (略)
>There is no standard way to discard unread characters from a stdio input buffer, nor would such a way be sufficient; unread characters can also accumulate in other, OS-level input buffers.
つーことでfflushは書き込みのフラッシュ専用で、読み込みについては定義されていないのか。