i wanted to know how to use fgets(); to asked the user for a string. instead of using scanf to scan for a string instead becasue scanf can cause buffer overflow.
can someone give me an example
for examaple
Code:#include <stdio.h> main() { char name[25]; printf("name is"); scanf("%s",&name); // this is not good because it can cause overflow if my string is larger thatn 25. so how do you use fgets }
fgets(name,25,stdin);
1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
3. Get rid of conio.h and other antiquated DOS crap headers.
4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.
what the hell is stdn
It's kinda like stdin, except it doesn't have an i.
Quzah.
Hope is the first step on the road to disappointment.
i mean what is stdin. can someone one tell me please. i want to get better at programing
You should discover the joys of a search engine. In the couple of minutes between posts, you didn't think to type 'stdin' in a search engine? Or even into the search field of this forum?
Quzah.
Hope is the first step on the road to disappointment.
that is what a forum is for ask question
A forum is not a replacement for a search engine and you using what I assume is contained in your cranium...a brain?
That's true but you could at least imagine that this is a question that has been asked hundreds of thousands of times, and you COULD do a search for stdin.Originally Posted by mouse666666
Let me google that for you
1. Get rid of gets(). Never ever ever use it again. Replace it with fgets() and use that instead.
2. Get rid of void main and replace it with int main(void) and return 0 at the end of the function.
3. Get rid of conio.h and other antiquated DOS crap headers.
4. Don't cast the return value of malloc, even if you always always always make sure that stdlib.h is included.
He's probably got it in a C book some place, and just didn't bother looking it up.
Quzah.
Hope is the first step on the road to disappointment.
FTR,
you can still overflow the stdin buffer with fgets()... won't be a spectacular crash, but you'll likely lose input data and make your program all wonky.
likewise, you can make scanf() protect the input variable from having an overflow.
just sayin'
You have no idea what you're talking about, or at least how to correctly word what it is you think you're talking about.
Quzah.
Hope is the first step on the road to disappointment.
its late here, im not expressing clearly:
fgets, if you dont size your char buffer properly , will leave uncollected input in the input stream. i shouldnt have said overflow. but the uncollected input will (unless the routine is sufficiently error-checked) will most likely cause the operation of the program to fail.
scanf if formatted correctly, can protect the char buffer from being overflowed.
all i'm saying is that scanf is not Teh Evil, and fgets is not Teh Messiah. though for new users, its probably best if they stay away from scanf
