2 very noob questions

This is a discussion on 2 very noob questions within the C Programming forums, part of the General Programming Boards category; \n is just another character that printf() doesn't care about and doesn't do anything special with. What you may be ...

  1. #16
    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    \n is just another character that printf() doesn't care about and doesn't do anything special with. What you may be confusing this with is how file are buffered. Output/Input can be delayed until the file is closed or until a "\n" is printed. stdio works this way, though I'm not sure if stdout does. (You can fflush(stdout); if needed...) Besides, there is no good reason for printf to specially treat or dislike a \n.

    You can always read the manual on printf, which never mentions \n. Nor does anything I can find.

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     if((string = strchr(firstname, '\n') != NULL)
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  2. #17
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    The 'failing to include '\n' in printf() could lead to undefined behavior' was a topic on comp.lang.c a long long time ago. I remember the professor from St Petersburg State University in Russia actually had given a URL (from the standard) where it stated this. Okay, I need to find the thread.

  3. #18
    Just Lurking Dave_Sinkula's Avatar
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    Are you sure it isn't something like this?
    Whether the last line requires a terminating new-line character is implementation-defined.
    http://web.archive.org/web/200502070...aft.html#4.9.2
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  4. #19
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    Dave,

    Yes, that smells like what the good professor was talking about at the time. Okay, since it is starting to become apparent that I make a fool out of myself in front of the smart people, combined with the fact my reading comprehension blows, do you wish to enlighten me (and the rest of us) on the whole '\n' with printf() thingy?

  5. #20
    Just Lurking Dave_Sinkula's Avatar
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    I'd rather not -- I've been a bit distracted lately. How about this?

    Basically I always try to ensure that the last output of a program ends in a newline, and that I fflush(stdout) when I want to see a prompt without a newline (aided by a preferred environment that does not display them otherwise).
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

  6. #21
    Registered User whiteflags's Avatar
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    Actually it seems better to not use printf unless you have an actual format string.

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