Thread: scanf vs fgets?

What would you guys recommend best for adaptation for future stuff. Iv read on various resources that scanf has its probs and such, and that its wiser to use fgets along with the string scanf for better input of users. Do u guys agree? Recommend it??

O btw Practical C Programming uses the fgets approach, which is quite ok the way i see it. Just wanna know ur responses. And why it would be or not be ok.

There once was a guy named Matus,
Who pondered, "Which better, scanf or fgets?"
The folks on the forum knew best
and without too much foray or jest
They recommended the use of fgets.

Originally Posted by Dino

There once was a guy named Matus,
Who pondered, "Which better, scanf or fgets?"
The folks on the forum knew best
and without too much foray or jest
They recommended the use of fgets.

Lol, cool ryhmes man, i need a partner for my upcoming book with poems, lol, care to send one if u write , good to know, im switching to fgets now though

Originally Posted by itCbitC

There is no bounds checking in scanf() so it doesn't know where to stop and the program can abend with sigsegv so better to use fgets() for reading the input stream followed by using sscanf() for parsing it.

Yep yep got it! Let see more replies,

>What would you guys recommend best for adaptation for future stuff.
It depends on what you're doing and how experienced you are with scanf. I usually recommend fgets and sscanf because too many people have no clue how to properly use scanf, but those same people probably wouldn't understand the better recommendation of fgets and a tailored parsing scheme. However, fgets+sscanf doesn't solve the problem of not fully understanding scanf (because sscanf has basically the same behavior), it just makes it easier to use by decoupling what are really two separate tasks: reading input and parsing input.

I'm not sure what you've read, but the reality is that scanf is too complicated and quirky to be a good choice in bulletproof code. Ideally you would use a rough equivalent to fgets followed by a parsing algorithm using something solid, strtol or strtod for example.

So I don't agree with your book, because most of scanf's problems still exist with the fgets+sscanf pairing. But I also don't agree that scanf itself is the problem. It's the programmer using scanf who doesn't know how to use it correctly.

Where I work there's a joke rule: If you haven't implemented scanf, you're not allowed to use it.

>There is no bounds checking in scanf()
Incorrect. There is bounds checking in scanf, but it's not automagic as many seem to expect. The following will never overflow the array:

Code:

char buf[256];

scanf ( "%255s", buf );

Originally Posted by Prelude

>What would you guys recommend best for adaptation for future stuff.
Where I work there's a joke rule: If you haven't implemented scanf, you're not allowed to use it.

>There is no bounds checking in scanf()
Incorrect. There is bounds checking in scanf, but it's not automagic as many seem to expect. The following will never overflow the array:

Code:

char buf[256];

scanf ( "%255s", buf );

Hmm ya i guess i have to agree with you Prelude, i guess as time goes by, ill be able to learn stuff. But thanks for the comments.

Originally Posted by master5001

Oh come on now, that should for sure go on your top quotes.

Yup sure does, i laughed when i read it!

The girl from Regina knew action
She had a huge and hairy contraption
All the boys knew
What she carried wasn't the flu
But that didn't stop the attraction

Originally Posted by master5001

You should hear what he wrote about the girl from Regina.

haha this dude should go for rapping. Umm hey so take this for instance:

Code:

char temp[50];
int i;
int j;
int m;


fgets(temp,sizeof(temp),stdin);
sscanf(temp,"%d",&i);

and then i could use that same temp for other vairable right, cuz its just a temp. For instance if later i wanted to read info for int j, int m etc.