09-16-2005
Quote:
Originally Posted by mridula
i m aware abt fread(), fwrite(), fseek()... but using these allows the pointer to be moved 1 character at a time. Is there a way i could jump directly to a line if i know the line number?
not so !
with fseek - file pointer can be repositioned anywhere within the file
if the file records are of standard length ( for ex: each and every line of the file contains x chars)
then to switch to nth line
fseek(filePtr, (n * x) + 1, SEEK_CUR);
(assuming \n as the default line separator in the file)
SEEK_CUR is the whence position.
use
man fseek you will get the required info
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LEARN ABOUT REDHAT
fwrite
FREAD(3) Linux Programmer's Manual FREAD(3)
NAME
fread, fwrite - binary stream input/output
SYNOPSIS
#include <stdio.h>
size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
DESCRIPTION
The function fread reads nmemb elements of data, each size bytes long, from the stream pointed to by stream, storing them at the location
given by ptr.
The function fwrite writes nmemb elements of data, each size bytes long, to the stream pointed to by stream, obtaining them from the loca-
tion given by ptr.
For non-locking counterparts, see unlocked_stdio(3).
RETURN VALUE
fread and fwrite return the number of items successfully read or written (i.e., not the number of characters). If an error occurs, or the
end-of-file is reached, the return value is a short item count (or zero).
fread does not distinguish between end-of-file and error, and callers must use feof(3) and ferror(3) to determine which occurred.
CONFORMING TO
The functions fread and fwrite conform to ANSI X3.159-1989 (``ANSI C'').
SEE ALSO
read(2), write(2), feof(3), ferror(3), unlocked_stdio(3)
BSD MANPAGE
1996-05-17 FREAD(3)