Thread: C program to find a line in a file and print it

Hi!

I can write a program to find a string in a file, write it to a different file, increment an int number in the file. But I can't find an example to find a line in a file which contains the string I need and then print the whole line.

Example:
search for String: 0x22 0x023 0x24
if String is found on line 9
print the whole line 9, or print until you find a custom terminating character like "0x9999 "

result must be: print 0x22 0x23 0x24 0x25 0x26 0x27 0x28.

Code:

#include <stdio.h>

int main(void)
{
  FILE *ifp, *ofp;
  char *mode = "r";
  char outputFilename[] = "out.list";
  char username[9];  /* One extra for nul char. */
  int score;

  ifp = fopen("in.list", mode);

  if (ifp == NULL) {
    fprintf(stderr, "Can't open input file in.list!\n");
    exit(1);
  }

  ofp = fopen(outputFilename, "w");

  if (ofp == NULL) {
    fprintf(stderr, "Can't open output file %s!\n", outputFilename);
    exit(1);
  }

  while (fscanf(ifp, "%s %d", username, &score) == 2) {
    fprintf(ofp, "%s %d\n", username, score+10);
  }

  fclose(ifp);
  fclose(ofp);

  return 0;
}

EDIT:
The simplest best I found is to find the string I am looking for(0x22 0x23 0x24 in this case) and print until the custom terminating character, but I don't how does the auto incrementation of fscanf will work in this case and I want to know the other case too.