counting file characters with fseek

Question

i want to count file chars like this :

#include <stdio.h>
#include <stdlib.h>

int main(){
    int d=0;
    char filename[25];
    FILE *file;
    printf("Enter file name to be read (Text File!) : ");
    gets(filename);
    file = fopen(filename, "rt");
    if(file == NULL){
        printf("Failed to open file...");
        exit(1);
    }
    fseek(file, 0L, SEEK_SET);
    while( !feof(file) ){
        fseek(file, 1L, SEEK_CUR);
        d++;
    }
    printf("%d", d);
}

after that im printing d and it value is 0.. and the file dose have chars. about 150 chars..

@alk: It's Windows standard for 'text' as opposed to 'binary' file. It isn't necessary; it is allowed on Windows. — Jonathan Leffler, Mar 15 '14 at 15:56
When I run this on my Debian system, the `while` loop never terminates, because the `fseek()` call doesn't set the file's EOF flag. (Seeking past the end of a file isn't an error, since you can seek and then write to make the file larger.) — Wyzard, Mar 15 '14 at 15:57
_For a text stream, either offset shall be zero, or offset shall be a value returned by an earlier successful call to the ftell function on a stream associated with the same file and whence shall be SEEK_SET.,_ — BLUEPIXY, Mar 15 '14 at 16:01
@alk [n1256.pdf](http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf) 7.19.9.2 The fseek function -4 — BLUEPIXY, Mar 15 '14 at 16:10
Interesting, so you want to imply the way the OP uses `fseek()` is undspecified bahaviour? @BLUEPIXY — alk, Mar 15 '14 at 16:14
If the objective is to 'count chars', does it matter if a new line may be represented by 1 or 2 bytes? If no, simply use `fstat` to get the file *length*; if yes, include logic to check each code read. — Jongware, Mar 15 '14 at 16:42

score 2 · Answer 1 · answered Mar 15 '14 at 16:07

2

fseek() allows you to seek beyond the mark of EOF.

To get the file size, you could fseek(file, 0, SEEK_END) and then call ftell(file).

To read character by character, you could use for (i = 0; fgetc(file) != EOF; i++);.

answered Mar 15 '14 at 16:07

Arjun Sreedharan

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thats the strangest thing. im doing it like that: .. (i dont know how to add code tags...im new) for (i = 0; fgetc(file) != EOF; i++); and i get i = 0 but there is chars in the file.. is i fwrite it to array then all works great. but i wand to malloc the array. – shlomi93 Mar 15 '14 at 21:02
@user3423498 worked out well for me. here's the code i tested http://pastebin.com/ej9tyPzL – Arjun Sreedharan Mar 15 '14 at 21:20
did it like you said. fseek(file, 0, SEEK_END) and then call ftell(file). – shlomi93 Mar 15 '14 at 21:37

alk · Answer 2 · 2014-03-15T16:10:26.280

1

I'm wondering if the program ever returns, as per fseek()'s documentation feof() shall never return anything <>0:

A successful call to the fseek() function clears the end-of-file indicator for the stream

To determine the file size using fseek() do:

FILE * pf = ...;

fseek(pf, 0, SEEK_END);
long size = ftell(pf);

edited Mar 15 '14 at 16:10

answered Mar 15 '14 at 15:57

alk

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...thus making this program just a slightly odd example of [“while( !feof( file ) )” is always wrong](http://stackoverflow.com/questions/5431941/while-feof-file-is-always-wrong) – Mar 15 '14 at 16:02
1

ftell : The return value is implementation-defined if the text stream. – BLUEPIXY Mar 15 '14 at 16:27

score 0 · Answer 3 · answered Mar 16 '14 at 04:30

0

i did it like this at the end and it work.

fseek(file, 0, SEEK_END);

and then call ftell(file);

befor i tryed to do it like that :

for (i = 0; fgetc(file) != EOF; i++);

and it didnt worked...but now it is 0.0 Thank you all..!

answered Mar 16 '14 at 04:30

shlomi93

1
1

counting file characters with fseek

3 Answers3