Thread: Problems with c-style strings

Originally Posted by possik

ok , i checked the file stream.

Code:

 fstream f;

        f.open(filen.c_str(),ios::out|ios::in|ios::binary);
		num=f.fail();

after these commands in main() function, the fail bit of the stream is set to 1.
but i don't why?
which types of error could it be?

could it be the string converting to c-style string/?

The conversion to c-style string in the filename is necessary, not a problem. If you expect this filename to exist, that should be something you need to check (i.e. that it does exist). Your current working directory may not allow files to be created there, depending on where you're running this from. I wish open would set errno.

YAYAYYAYAYAYYAYA i fixed the problem!!!

so the problem was that i opened the file in ios::in|ios:ut|ios::binary

but the files weren't yet created , so the compiler opened the file with a failbit!!!
so instead of

Code:

 fstream f;

 f.open(filen.c_str(),ios::out|ios::in|ios::binary);

i made something like this :

Code:

fstream f;

        f.open(filen.c_str(),ios::out);
		f.close();
		f.open(filen.c_str(),ios::in|ios::out|ios::binary);