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Creating a Sequential Access File
(Writing TO a file!)

A file is a container for data.  Think of a file as a  drawer in a file cabinet which needs to be opened and closed.  Before you can put something into a file, or take something out, you must open the file (the drawer).  When you are finished using the file, the file (the drawer) must be closed.

Steps to create (or write to) a sequential access file:

1.  Declare a stream variable name:

 ofstream fout; 

//each file has its own stream buffer

ofstream is short for output file stream
fout is the stream variable name 
(and may be any legal C++ variable name.)
Naming the stream variable "fout" is helpful in remembering
that the information is going "out" to the file.

2.  Open the file:"scores.dat", ios::out);

fout is the stream variable name previously declared
"scores.dat" is the name of the file
ios::out is the steam operation mode
(your compiler may not require that you specify
the stream operation mode.)

3.  Write data to the file:

fout<<"Mr. Spock\n";

The data must be separated with space characters or end-of-line characters (carriage return), or the data will run together in the file and be unreadable.  Try to save the data to the file in the same manner that you would display it on the screen.

If the iomanip.h header file is used, you will be able to use familiar formatting commands with file output.



4.  Close the file:

fout.close( );

Closing the file writes any data remaining in the buffer to the file, releases the file from the program, and updates the file directory to reflect the file's new size.  As soon as your program is finished accessing the file, the file should be closed.  Most systems close any data files when a program terminates.  Should data remain in the buffer when the program terminates, you may loose that data.  Don't take the chance --- close the file!


Required header:


allows classes ofstream and ifstream to become available.



When creating a new file, if a file of the same name already exists, it will be erased and replaced with the new file.



A text editor can be used to view, or create, a file.



If getline( , ) is used to obtain information for a file, be sure to use endl to format the file.  Do NOT use whitespace (" ") to format the file -- you will not be able to read the data at a future date.



Always close your files as soon as you are finished accessing information.