[MacmanX]

Hi all,
Since installing OSX, I've been thinking about my old unix days in college. Knowing that OSX programmes are written in objective C, I decided to learn C and then work my way up to objective C once some good books were out. However, I've come upon my first stumbling block. My book, "C for Dummies vol.1", teaches the gets() function as a way to get keyboard input. So, I coded the exercise programme and compiled it with no problem. However, when I run it from the command line I get: "This programme uses the gets() function which is dangerous" (or something like that.) Why is gets() dangerous? Should I substitute scanf(), or is there some other function I should be using instead of gets()? Your help will be much appreciated by a "programmer in training". Cheers,
Derrick

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10:00 conocí a Apple. 10:30 trabajé con Apple. Apple Computer®

[clarkgoble]

gets() is indeed dangerous and rarely works as advertized. In general you should write your own equivalent. (Speaking as one who learned this the hard way years ago and who didn't have a compiler who provided this helpful warning)

Why a book would encourage using this function is beyond me.

You should also, as you use stdio, read carefully the requirements. I had a class a few weeks ago with a subtle bug because of the limitations stdio had switching between reading and writing without flushing. I've noticed that a lot of my bugs end up being due to making assumptions about these things. . .

While it's undoubtedly overkill for what you are doing, anyone else using stdio might find the book The Standard C Library helpful. It's saved my butt a few times. It is also interesting seeing how the standard function libraries were written.

[parallax]

gets() is evil because it can "overflow the buffer." This means that it writes past the memory allocated to the buffer (the string you're storing the value of gets() to).

Remember next time to search the forum for the question you're asking (Sorry, I know it's a pain ). The question was asked by Lars-1 a week or two ago.
http://forums.macnn.com/cgi-bin/Foru...ML/000705.html

[MacmanX]

Thanks!
I will continue on my path to C enlightenment.

Parallax,
I hadn't noticed the search option before. Thanks. That will save me a lot of time digging through posts.

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10:00 conocí a Apple. 10:30 trabajé con Apple. Apple Computer®