StdIO Binary Round Trip

The shortest demonstration that the C++ iostream classes can do raw binary work. ofstream::write dumps the four bytes of a DWORD straight into a file (no text conversion, no newline), and ifstream::read pulls those same four bytes back out into another DWORD, which is then printed. Useful as a reference when you want portable-looking binary file handling without dropping down to Win32 CreateFile/ReadFile - for example persisting small structs or magic-number headers.

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include <Windows.H>
#include <StdIO.H>
#include <StdLib.H>
#include <IOStream.H>
#include <FStream.H>

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

int main(void)
{
    DWORD OutDword = 840823110;
    DWORD InDword  = 0;

    //--------------------------------------------------------
    ofstream FOut;

    FOut.open("C:\\Test.txt");
    if(FOut.good() == FALSE)
        return 0;

    FOut.write((char *)&OutDword, sizeof(DWORD));

    FOut.close();

    //--------------------------------------------------------

    ifstream FIn;

    FIn.open("C:\\Test.txt");
    if(FIn.good() == FALSE)
        return 0;

    FIn.read((char *)&InDword, sizeof(DWORD));

    cout << InDword << endl;

    FIn.close();

    //--------------------------------------------------------

    return 0;
}

Two practical notes: open the streams in binary mode (std::ios::binary) so no translation layer ever touches the bytes, and remember this round trip only works between machines with the same endianness and DWORD size - for anything exchanged across platforms, serialize explicitly.