fstream reading from a file and writing to a file

[SmileeTiger]

Can someone give me some sample code to read from and write to a file in text mode using fstream?


Thanks

 

[2ffat]

I'm going from memory on this but you should get the idea. BTW, I'm showing this for Builder but the same principles apply to standard C++. In your header file you will need to add:

#include <fstream>

Then in your function you could do something like this:

ofstream ArchiveFile; // opens stream named ArchiveFile for output
ArchiveFile.open("OutPut.dat", ios::out | ios::app); // opens for append so original isn't overwritten (out is redundant)
if (!ArchiveFile)
{
    // Stop processing! There is an error.
    Application->MessageBox("Cannot create archive file.", "File Error", MB_OK); // error message box
    return; // get out of function
}

ifstream FNFile; // stream set up for input
FNFile.open("File2Get.dat");

if (!FNFile)
{
    // Error opening file! Stop processing.
    Application->MessageBox("Cannot open file to archive.", "File Error", MB_OK);
    ArchiveFile.close(); Close open output file
    return; // Get out of function
}
else
{
    // No errors so let's process
    string ArcLine; // this will be the line to copy from one file to another
    while (getline(FNFile, ArcLine, '\n'))
    {
        // Put line to output
        ArchiveFile << ArcLine << endl;
        // You could also do a character by character copy, too
    }
}

// All done so close files
ArchiveFile.close();
FNFile.close();

There are several ways to go this so don't think this is the only way. You may have to put

std::

in front of the streams, getline, ios, etc. depending on which version of the compiler you use and how you name your namespaces. James P. Cottingham

When a man sits with a pretty girl for an hour, it seems like a minute. But let him sit on a hot stove for a minute and it's longer than any hour. That's relativity.
[tab][tab]Albert Einstein explaining his Theory of Relativity to a group of journalists.