Thread: count signs in .txt file bug?

Your file reading loop is wrong, because feof() doesn't work how you expect.

In particular, you have an fread() that will fail to read something, but you don't detect that.

Code:

while ( fread(&current,1,sizeof(char),test) == 1 ) {
    if(current == ' ' || current == '\n'){
        pos2--;
    }
}

Does that actually work? It looks like the pos1 and pos2 business is just to count the number of characters in the file, then you subtract from pos2 each time... but that doesn't make sense to me. Why not just read and count the characters instead of trying some fancy tricks with number of characters and subtraction?

No, '\n' is not "twice as large".
The problem is that you are reading a file with Windows line endings ('\r' '\n') in text mode, so your fread will never see the '\r' characters.
However, the fseek and ftell have no way to ignore the '\r' chars, so they count them and therefore you need to subtract 2 for every '\n' you see.
It would be more portable to open the file in binary mode and explicitly deal with the '\r' chars.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
 
long int countSigns(FILE *fin)
{
    fseek(fin, 0, SEEK_END);
    long int pos = ftell(fin);
    fseek(fin, 0, SEEK_SET);
    for (char ch; fread(&ch, 1, 1, fin) == 1; )
        if (ch == ' ' || ch == '\n' || ch == '\r') // or isspace(ch)
            --pos;
    return pos;
}
 
// A more usual way to do it. (Also works fine in text mode.)
long countNonWhitespace(FILE *fin) {
    long count = 0;
    for (int c; (c = fgetc(fin)) != EOF; )
        if (!isspace(c))
            ++count;
    return count;
}
 
int main()
{
    FILE *fin = fopen("count.c", "rb"); // opening in binary mode
    if (!fin) { perror("fopen"); exit(EXIT_FAILURE); }
 
    printf("count: %ld\n", countNonWhitespace(fin));
    rewind(fin);
    printf("Zeichenzahl: %ld\n", countSigns(fin));
 
    fclose(fin);
    return 0;
}

Originally Posted by thmm

Doesn't the C Runtime replace \r\n with a single \n or is this only in C++ ?

That's the difference between "text" and "binary" modes in both C and C++.
In text mode, the '\r' chars are removed.
In binary mode they aren't.
The OP's problem counting newlines had to do with opening the file in text mode (so '\r' is ignored) but counting the total characters in the file using essentially binary-mode operations that do not ignore the '\r' chars (fseek, ftell).