Question

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;

int main() {

fstream inOutGrades( "grades.dat", ios::in | ios::out | ios::binary );

if ( !inOutGrades ) {
    cerr << "The file could not be opened." << endl;
    exit(1);
}

return 0;
}

//Output is 
The file could not be opened.

I’ve tried this program wioth QT and Code::blocks at windows 7 and lubuntu.They all can’t create the grades.dat file.

Answer 1

Remove ios::in and the file should be created. You cannot specify ios::in if a file does not exist. However, if you add ios::trunc you are able to specify both ios::in and ios::out since you are starting with an empty file.