Writing from a certain line in C

[strangist]

I have the following code, but even more is an algorithm but it is the final pint take more or less.

void function (char * insert) ( 
  Fila * copy; 
  Long a; 

  assert (copy = fopen ( "copia.txt", "aw")); 

  fseek (copy, 0, SEEK_CUR); 
  = ftell (copy); 

  fprintf (stdout, "I'm in character% d \ n", a); 

  fputs (insert copy); 
  fputs ( "\ n", copy); 

  fclose (copy); 
  ) 


  Main (void) ( 

  char * [4] = ( "Hello", "Gold", "americas", "Eloisa"); 
  int b; 
  char c [100]; 
  char * d; 
  char insertion [20]; 
  Fila * file; 

  if (! (file = fopen ( "file.txt", "r"))) ( 
  fprintf (stdout, "Error opening \ n"); 
  clearerr (file); 
  ) 

  fgets (c, 50, file); 
  d = strtok (c, ""); 

  while (d! = NULL) ( 

  for (b = 0; b <4 b + +) ( 
  if (strcmp ([b] d) == 0) ( 

  fprintf (stdout, "% s% = s are equal \ n", [b] d); 
  fprintf (stdout, "Inserts word to enter \ n"); 
  fscanf (stdin, "% s", & integration); 
  fprintf (stdout, "Thanks Wait .... \ n"); 
  function (integration); 
  system ( "sleep 02"); 

  Else () 
  fprintf (stdout, "% s% = s are not equal \ n", [b] d); 
  ) 

  ) 
  break; 
  ) 

  fclose (file); 
  return 0; 
  )

What I want is that the function which opens a file called 'copia.txt' for writing, there is some way to use fgets provided for positions after 11 characters and write from there and not just from the end (Seek_end) or the start (SEEK_SET) and could put the arrow after 11 characters and write there: /

[Calvin K]

if I am not mistaken,

fseek (copy, 11L, SEEK_SET);

[MrChris-]

What I want is that the function which opens a file called 'copia.txt' for writing, there is some way to use fgets provided for positions after 11 characters and write from there and not just from the end (Seek_end) or the start (SEEK_SET) and could put the arrow after 11 characters and write there: /

int fseek (IBF * stream, long int offset, int origin);

Parameters
Stream
Pointer to a file object that identifies the stream.
Offset
Number of bytes to offset from origin.
Origin
Position from where offset is added. It is specified by one of the following constants defined in <cstdio>:
SEEK_SET Beginning of File
SEEK_CUR Current position of the file pointer
SEEK_END End of File

fseek (copy, 11, SEEK_CUR);

Obviously in your original code (not what I will certainly come to appreciate) fseek does nothing for it asking that these moves 0 bytes from the current position. We can also use perfectly SEEK_SET and which is more logical in this case but not what we demand.

[strangist]

fseek (File, 10, seek_cur);

I have tried this in various ways. Even tested on instead uploaded -10 for example, and indeed according to the printf is located in that line, but when I write command to strip by the end of the text (I assume that by append) but if I 'write' I delete everything and I overwrites the text: / (write clear is supposed to work that way).

I had already tested line position as the two of you expressed here, and they seem not lie Quiz probe suggest that in this way when you start the post modify the code until before Posten, for which I was not riddled by saying that what I was doing was a stupidity ... as has happened on other occasions ... and that more rounds for the code actually works and does not give me an answer to because it works but is evil and is now in order ...

That exposes what had already done previously, does not work independently that the pointer is placed at x line does not write me from there, I wrote at the end (if I use append) or at home (write )....

Then looking into this situation, the problem really is not that I know of that position because I am aware that there is the problem here is append and write, there is some form or some function that allows me to write from that line, porke append and are helping not write much .....

Incidentally, while not actually going in the code that does not quiz post here to avoid insults superiors, took a if ... with sufficient for it.