/* capitalize the contents of infile and append to the infile
   by creating a temporary file */
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

main(int argc, char **argv)
{
  int c;
  FILE *fp, *tmp_fp;
  FILE *gfopen(char *file_name, char *mode);

  if (argc != 2) {
	fprintf(stderr, "\n%s%s%s\n\n%s\n\n",
	  "Usage: ", argv[0], " file-name",
	  "The file will be doubled and some letters capitalized.");
	exit(1);
  }
  fp = fopen(argv[1], "r+");
  tmp_fp = tmpfile(); /* tmpfile is defined in stdlib.h */
  while ((c = getc(fp)) != EOF)
	putc(toupper(c), tmp_fp);
  rewind(tmp_fp);
  fprintf(fp, "--\n");
  while ((c = getc(tmp_fp)) != EOF)
	putc(c, fp);
}

FILE *gfopen(char *file_name, char *mode)
{
  FILE *fp;

  if ((fp = fopen(file_name, mode)) == NULL) {
	fprintf(stderr, "Cannot open %s - bye!\n", file_name);
	exit(1);
  }
  return fp;
}