File IO question

[baxy]

Hi,

I have asked this question before but a seam to not understand how it works. So if someone would be so kind to give an example. So what i have is this peace of code:

#include <stdio.h>
#include <stdlib.h>



int main(int argc, char *argv[]){

FILE *fp;
char buff[91];
int x,y,c;
fp = fopen(argv[1], "r");

  while (fgets(buff, 10, fp) != NULL)    {
      if (buff[0] == '-'){
          printf("%s",buff);
      }	
      else if (buff[0] == '\n'){
		  continue;
	  }
      else if ((c=sscanf (buff,"%d  %d", &x, &y)) !=0){
        printf("%d,%d\n",x,y);
      }

  }
 
  fclose(fp);
 return 0;        
}

so what it does is it reads some file extracts some info and so on. Also here is the input file.

-first set
23 22
32 22
23 22
-second set
54 44
34 33
23 45
23 45

and this input is saved in file called in.txt

the way i run the program now is : ./prog in.txt

but i would like to run it like: cat in.txt | ./prog

so pipe it from stdout of cat how do i do this ??
baxy

[rags_to_riches]

Instead of using fopen and fp1, you use stdin for your fgets(). You don't need to fopen() it.

[baxy]

thnx

[christop]

You win the useless use of cat award!