To make sure that there is no CR/LF translation on non-Unix computers, you have to use the following lines to open streams to files with binary data.
ofstream os("output.flt", ios::out | ios::binary);
ifstream is("output.flt", ios::in | ios::binary);
For Visual C++, when using fstream.h, use in addition the flag ios::nocreate. Otherwise you can open a non-existing file for reading, without complaining. (This is not necessary when using fstream).