sopherwenxin學習筆記

關于scanf的返回值，MSDN里是這樣寫的：
Both scanf and wscanf return the number of fields successfully converted
and assigned; the return value does not include fields that were read but
not assigned. A return value of 0 indicates that no fields were assigned.
The return value is EOF for an error or if the end-of-file character or the
end-of-string character is nocountered in the first attempt to read a character.
如：
scanf("%d%d", &a, &b);
如果a和b都被成功讀入，那么scanf的返回值就是2
如果只有a被成功讀入，返回值為1
如果a和b都未被成功讀入，返回值為0
如果遇到錯誤或遇到end of file，返回值為EOF。