14.2. Files and Streams

C++ views each file simply as a sequence of bytes (Fig. 14.1). Each file ends either with an end-of-file marker or at a specific byte number recorded in an operating-system-maintained, administrative data structure. When a file is opened, an object is created, and a stream is associated with the object. In Chapter 13, we saw that objects cin, cout, cerr and clog are created when <iostream> is included. The streams associated with these objects provide communication channels between a program and a particular file or device. For example, the cin object (standard input stream object) enables a program to input data from the keyboard or from other devices, the cout object (standard output stream object) enables a program to output data to the screen or other devices, and the cerr and clog objects (standard error stream objects) enable a program to output error messages to the screen or other devices.

Fig. 14.1. C++’s simple view of a file of n bytes.