How to read input from stdin

[johnny8888]

I am writing the c program using linux shell, i want to save a batch of the input parameter in the text file, input.txt
i want to run my program like this
./a.out < input.txt
at that time, i need to save the input list in the char* array[10]
could somebody give me any hints of source code?

[quzah]

You want command line arguments: Cprogramming.com FAQ > Accessing command line parameters/arguments


Quzah.

[johnny8888]

i am not wanna have argv command.........i want to use scanf to the stdin, is that ok??

[CommonTater]

Yep. Should work provided you know what to expect from the command line.

[johnny8888]

My situation is that I stored all the parameter in the text file call a.txt
i need to run my file in Linux server like this:
./a.out < a.txt
I am try to assign thoes parameter in the array of char*

i wrote the code like this:
char *word[n];
for (i=0; i<count; i++)
scanf("%s", &word[i]);

unfortunately, the error message occured
"segmentation fault"
i have no idea of that problems
could any helps my to figure out this problem?
Thank you very much!!

[quzah]

That's just an array of pointers. You don't have them pointing to any memory you have allocated. Try using fgets to read into a temporary buffer, then find out the length of whatever it is you want to store, then allocate space (malloc), copy from the buffer to the new space (strcpy), and assign the new space to that pointer.


Quzah.

[BillyTKid]

char *word[n];
for (i=0; i<count; i++)
   scanf("%s", &word[i]);

char words[10][100];
int i;
for( i=0;i<10;++i )
  if( fgets(words[i],100,stdin) )
  {/* fgets doesn't ever add a '\n', therefore... */
    if( strchr(words[i],'\n') ) *strchr(words[i],'\n')=0;
  }

[quzah]

  {/* fgets doesn't ever add a '\n', therefore... */
    if( strchr(words[i],'\n') ) *strchr(words[i],'\n')=0;
  }

I'm not sure what your comment is supposed to mean, but that's an expensive way to try to get rid of the newline.


Quzah.