Flushing the input buffer

Is there a way to flush the input buffer like this:

Code:

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while ((ch = getchar()) != '\n' && ch != EOF);

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But without having to hit enter?
If you do this after calling fgets() you have to hit enter twice. I presented my problem to my instructor yesterday and no surprise he told me to use fflush(stdin). I didn't want to correct him, I just did it so I can pass (lucky for me it worked anyway). But is there another way to do it?

Not in standard C. Some implementations provide functions to do it (such as fpurge from BSD), but these are non-portable, obviously.

Also, what is the point of flushing stdin, even if you can? It's just going to annoy/surprise the user, if they are trying to automate a program by piping stuff to its stdin.

Well, I was calling fgets multiple time to receive data for different fields in a record. If somebody inputs 20 characters when they should only have input 10 then the next call to fgets will use that data that I no longer need.

> If somebody inputs 20 characters when they should only have input 10
> then the next call to fgets will use that data that I no longer need.
In that case, you detect whether it is a well-formed record (it has a \n at the end), or whether it is likely garbage because someone is trying to see if they can buffer-overflow your code.

If the fgets() returns a buffer with a \n, then process it.
If it doesn't have a \n, throw it away and keep junking input until you find either EOF or a '\n'

Thanks Salem. Good idea