fgets question 1

[Bangieff]

Hi all
Here is the situation:
I need a program that reads information from stdin and for example write it to stdout (the second part is not exactly the same but it's not important right now ). And that's what I wrote:

#include <stdio.h>

main()
{
char *str;
while (1)
{
if (fgets(str,124,stdin)!=NULL
{
printf(&quot;->%s\n&quot;,str);
}
}
}

and when I run: tail xxx.txt | ./a.out
I'm getting segmentation fault. I just hate this error
Can anyone tell me where the problem is
Thanks in advance

 

[smaniraja]

Yes, will get segmentation fault.

You have declared a pointer variable str, you are not allocated any space for that but your are reading a maximum of 124 characters for the file and storing to the unallocated pointer variable.

change the
char *str; statement to
char str[125]; or
keep char *str as it is and allocate memory for that before reading for the file.

put str = (char *) malloc( 125 * sizeof(char));
before the while statement and before the main functions }
put free(str);

Regards
Maniraja S