title: Overwriting lines in file in C
body: <p>I'm doing a project on filesystems on a university operating systems course, my C program should simulate a simple filesystem in a human-readable file, so the file should be based on lines, a line will be a "sector". I've learned, that lines must be of the same length to be overwritten, so I'll pad them with ascii zeroes till the end of the line and leave a certain amount of lines of ascii zeroes that can be filled later.</p>
  
  <p>Now I'm making a test program to see if it works like I want it to, but it doesnt. The critical part of my code:</p>
  
  <pre><code>file = fopen("irasproba_tesztfajl.txt", "r+"); //it is previously loaded with 10 copies of the line I'll print later in reverse order  
  
    /* this finds the 3rd line */
   int count = 0; //how much have we gone yet?
   char c;
  
   while(count != 2) {
    if((c = fgetc(file)) == '\n') count++;
   }
  
   fflush(file);
  
   fprintf(file, "- . , M N B V C X Y Í Ű Á É L K J H G F D S A Ú Ő P O I U Z T R E W Q Ó Ü Ö 9 8 7 6 5 4 3 2 1 0\n");
  
   fflush(file);
  
   fclose(file);
  </code></pre>
  
  <p>Now it does nothing, the file stays the same. What could be the problem?</p>
  
  <p>Thank you.</p>