Page 297 - DCAP404 _Object Oriented Programming

Object-oriented Programming

Notes cout << “\nEmpl Name: “ << EmployeeName;
cout << “\nAddress: “ << Address;
cout << “\nCity: “ << City;
cout << “\nState: “ << State;
cout << “\nZIP Code: “ << ZIPCode;
*/
cout << “\n\n”;

return 0;
}
Closing an opened data file is the simplest of all the data file operations. All you have to do is to
call the member function close() on the file stream hooked to the opened file. Once the file is
closed it cannot be read/written unless reopened. The syntax for the same action is,
File_stream_name.close();

Self Assessment

Fill in the blanks:
13. To perform file processing, you can declare an instance of an ………………….. object.

14. If you want to add things to an existing file then you must open it for appending by using
…………………… when opening the file.

13.6 Different Types of Files

A file is a collection of letters, numbers and special characters: it may be a program, a database,
a dissertation, a reading list, a simple letter etc. Sometimes you may import a file from elsewhere,
for example from another computer. If you want to enter your own text or data, you will start by
creating a file. Whether you copied a file from elsewhere or created your own, you will need to
return to it later in order to edit its contents.

The most familiar file systems make use of an underlying data storage device that offers access
to an array of fixed-size blocks, sometimes called sector, generally 512 bytes each. The file
system software is responsible for organizing these sectors into files and directories, and keeping
track of which sectors belong to which file and which are not being used. Most file systems
address data in fixed-sized units called “clusters” or “blocks” which contain a certain number of
disk sectors (usually 1-64). This is the smallest logical amount of disk space that can be allocated
to hold a file.
However, file systems need not make use of a storage device at all. A file system can be used to
organize and represent access to any data, whether it be stored or dynamically generated (e.g,
from a network connection).
Whether the file system has an underlying storage device or not, file systems typically have
directories which associate file names with files, usually by connecting the file name to an index
into a file allocation table of some sort, such as the FAT in an MS-DOS file system, or an inode in
a Unix-like file system. Directory structures may be flat, or allow hierarchies where directories
may contain subdirectories. In some file systems, file names are structured, with special syntax
for filename extensions and version numbers. In others, file names are simple strings, and
per-file metadata is stored elsewhere.

290 LOVELY PROFESSIONAL UNIVERSITY