C Primer Plus®, Third Edition

Terminating Keyboard Input

The program halts when # is entered, which is convenient as long as you exclude that character from normal input. As you've seen, however, # can show up in normal input. Ideally, you'd like a terminating character that normally does not show up in text. Such a character won't pop up accidentally in the middle of some input, stopping the program before you want it to stop. C has an answer to this need, but, to understand it, you need to know how C handles files.

Files, Streams, and Keyboard Input

A file is an area of memory in which information is stored. Normally, a file is kept in some sort of permanent memory, such as a floppy disk, a hard disk, or a tape. You are doubtless aware of the importance of files ...