Thread: To open or not to open ?

Hi,

I am sorry to labour this point, but I cannot understand why I cannot get a count of lines in a text file

Code:

void check_activity(FILE ** p_fp)
{
int diff = 0;
int result = 0;
int countA = 0, countB = 0;
int ch;

    printf("before this month, last month, difference percentage %d %d %d %d\n", countA, countB, diff, result);

if(!(p_fp[OUT_FILE]))
   printf("OUT_FILE is not open !!");


/*
   rewind(p_fp[OUT_FILE]);
*/

   fseek(p_fp[OUT_FILE], 0, SEEK_SET);
   while((ch = fgetc(p_fp[OUT_FILE])) != EOF)
      if(ch == '\n')
         countA++;

printf("first count of OUT_FILE [%d]\n", countA);

   while((ch = fgetc(p_fp[LAST_FILE])) != EOF)
      if(ch == '\n')
         countB++;


   /* establish which is the largest file */
   if(countA > countB)
   {
      diff = countA - countB;
   }
   else
   {
      diff = countB - countA;
   }

   /* get the percentage to test */
   result = countA / 10;

   if(diff > result)
      cirp_process(p_fp);

    printf("after this month, last month, difference percentage %d %d %d %d\n", countA, countB, diff, result);
}

/* test run */
$ cirp_process september.SND august.SND
before this month, last month, difference percentage 0 0 0 0
first count of OUT_FILE [0]
YES
after this month, last month, difference percentage 0 10 10 0
$

I have swapped the order of the files as arguments, I have swapped the order of calling the parameter definitions, I have swapped the cut-n-paste while routines round the other way, I have tried rewind and fseek and I have tested to see that the file really is open.

I have also made a small function with one routine and sent the two files to it just to see, and still get the same result.

Code:

int get_count(FILE ** fp, int text_file)
{
int ch, count = 0;

   while((ch = fgetc(fp[text_file])) != EOF)
      if(ch == '\n')
         count++;

   return count;
}

/* test run */
$ cirp_process september.SND august.SND
before this month, last month, difference percentage 0 0 0 0
count of OUT_FILE [0]
count of LAST_FILE [10]
after this month, last month, difference percentage 0 10 0 0
$

However, what I do not know is this...

If I start a process and open some files, say two files, one already exists and the other doesn't, and I read the one that does, and write to the one that doesn't, do I have to close that new file and then re-open it before I can work on it ?

If that is the case, it is going to make the program a bit messy, as at present all files are opened at the start and closed at the end, and I would have to do a separate process just for this file.


tia,

and I need to make an even bigger apology

first, thanks to everyone who has posted and helped me.

The reason I am not counting any records in this particular file, is because of the way I am opening it

Code:

   /* Output file */
   strcpy(out_file, inp_file);
   strcpy(out_file + (strchr(out_file, '.') - out_file), OUT_SUFFIX);
   if(!(fp[OUT_FILE] = fopen(out_file, "w")))
      error_func("In file_open().", "Error : fopen(OUTPUT_FILE)", SYS | FATAL);

as you can see, I am opening it in write mode - ooops