How to create a binary i/o file?

[cousinoer5]

This program is supposed to ask the user if they want to open up an existing file, or create a new one. With an existing file, I have no problem, since it already exists. Creating a new one however, stumps me. My professor told me not to use a trick (before, I just opened a new file as an output file so it creates, then close it, and open it again in the proper mode), since I can't use that for this program, I'm at a loss of how to create a file and have it ready for binary file i/o without using any close and reopen tricks. Here's the relevant code:

                do 
		{

			cin.clear();
			cin.ignore();
			cout << "Enter the name of a new file: ";
			cin.getline(fname, 30);
			fio.open(fname, ios::out || ios::in || ios::binary || ios::trunc);
			if (!fio)
			{
				cout << "File does not exist, try again? (y/n) ";
				choice = getYesNo();
			}
		}
	while (choice == 'Y' && !fio);

I thought trunc would work (it wouldn't matter that it deletes that data since it's creating a file), but it still says file does not exist. I know you guys dislike homework problems, but the rest of the program is done (it's quite a big program with error checking and manipulating the file in many ways), this is just one little thing that is bugging me. Any help is appreciated.