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From: rjohnson@shell.com (Roy Johnson)
Newsgroups: comp.lang.c
Subject: Re: Creating files with variable suffixes at run time
Message-ID: <RJOHNSON.91Apr17105125@olorin.shell.com>
Date: 17 Apr 91 15:51:25 GMT
References: <1991Apr12.103621.8907@umiami.ir.miami.edu>
	<22418@yunexus.YorkU.CA>
Sender: usenet@shell.shell.com (USENET News System)
Organization: Shell Development Company, Bellaire Research Center, Houston, TX
Lines: 43
In-Reply-To: racine@yunexus.yorku.ca's message of 16 Apr 1991 14:20:45 GMT


In article <22418@yunexus.YorkU.CA> racine@yunexus.yorku.ca (Jeff Racine) writes:
>I would like to create separate files for each variable with names
>like foo1.dat, foo2.dat, and so forth. The problem is that the number
>of variables is variable, so I cannot hard code a number of files to
>be open. The solution can open a file, write data, close the file,
>open the next, write data, close the file etc. that is, the files do
>not have to be open simultaneously. I hope this description is
>sufficient.

>Has anyone done this successfully? If so would you kindly outline your
>solution? If not can someone see an easy way of doing this?

This is a job for one of my favorites: freopen()

int main(argc, argv)
  unsigned argc;
  char     *argv[];
{
  int numfiles, i;
  char filename[50];

  /* Read number of variables from argv[1] */
  if (sscanf(argv[1], "%d", &numfiles) != 1) {
    perror("scanf");
    exit(1);
  }

  for (i = 0; i < numfiles; ++i) {
    sprintf(filename, "foo%d.dat", i);
    if (freopen(filename, "w", stdout) != stdout) {
      perror("freopen");
      exit(1);
    }
    /* Write all your data to the foo#.dat here */
  }
  fclose(stdout);
  return 0;
}
--
=============== !You!can't!get!here!from!there!rjohnson ===============
Feel free to correct me, but don't preface your correction with "BZZT!"
Roy Johnson, Shell Development Company