C: replacing a line in a file....

[Structural Integrity]

How can I replace a line in a file? Is there actually a C function for that as none is listed in my book.

I want to search for a line containing a certain word, then replace the word and value behind it.

[meglamaniac]

If you're using C you could probably do something with fgetc (scan for 10/13 and count them, so you know which line you're on).

As for replacing, the only way I know is to rewrite the file, although I've never done much with file operations.

If you allready know the line to replace, the pseudocode might go something like:

open file
open newfile
copy contents of file to newfile until you reach the line to replace
scan line for word, store file pointer value at the START of the word
move file pointer backwards to start of line again
copy the line to newfile UP TO the word position
output the new word
scan to the next value 32 (the space between the word you want to skip output of and the next one)
continue copying til EOF
erase file, rename newfile

Obviously, easier said than done.
[edit]
Pseudocode corrected - i missed the bit about you wanting to look for a word
[/edit]

[Pitchfork]

I don't know a function for replacing a line in C, what I'd do is:
- open the input file for read
- open a temporary (empty) file for write
while(!eof(inputFile)) {
- read line from input file
- search for your word
- if it contains the word replace the line with the new one else leave it as it is
- write the line to the temp file
}

now you should have what u wanted in the new file, pretty easy, eh

[Structural Integrity]

Easy? I was actually hoping that there was a way to replace a line...

=/

Oh how I miss mIRC script.... life was so much easier back then...

[Slidey]

int grep(char *data, char *grepfor1, char *grepfor2)
{
    unsigned char *walker, *buf2;
    char *line;
    char buf[255];
    int hit = 0;

    buf2 = mmalloc(strlen(data) + 1);
    memcpy(buf2, data, strlen(data) + 1);

    for (walker = buf2; *walker; walker++)
        if ((*walker < 32 || *walker > 127) && *walker != '\n' && *walker != '\r' && *walker != 9)
            *walker = '.';

    walker = buf2;
    while ((line = strsep(&walker, "\n"))) {
        //if (opt->debug > 1) printf("grep %s\n", line);
        if (strstr(line, grepfor1) || strstr(line, grepfor2)) {
            //if (opt->debug > 1) printf("^^^ HIT\n");
            snprintf(buf, sizeof(buf), "%s\n", line);
            hit++;
        }
    }
    free(buf2);

    return(! hit);
}

or thereabouts