Input and Output concurrently

Hi,

I would like to know if it is possible to read a file and write to the same file at the same time.
For example, if I have

Code:

#include <fstream>
// and other headers


using namespace std;

string temp_string;
char result;


fstream studfile;
studfile.open("student.dat", ios::in | ios::out); // Is this correct?

while (!studfile.eof() ) {
     getline ( studfile, temp_string);
     studfile << "Results: " << result << endl;
}

Is there any way to manipulate a .dat file while reading it?
I've checked quite a couple of sites, but there are only solutions for binary files..

Thanks! =)

It should be possible. Are you having problems?
Do you mean doing both reading & writing in a single thread, or trying to read and write at exactly the same time? If it's the latter, then you should be using some kind of mutex to serialize either reading or writing but not both.

If you're reading and writing fixed length records, yes.
If you're reading a text file and trying to make each line longer, NO!

Oh, and read the FAQ on why your use of eof() is bad.

here it should be enough testing as:

Code:

while (studfile)
{
    //...
}

but why studfile.eof() is bad ?
and is my suggestion better ?

> but why studfile.eof() is bad ?
Hello! - Read the FAQ!

kindly can you point me to the FAQ? because the FAQ of this board only mentions that C File I/O feof() is bad. it says nothing about C++ eof().

http://faq.cprogramming.com/cgi-bin/...&id=1043284351