The Format Flags

C++’s Predefined Streams

When a C++ program begins execution, four built-in streams are automatically opened. They are listed here:

Stream	Meaning	Default Device
cin	Standard input	Keyboard
cout	Standard output	Screen
cerr	Standard error output	Screen
clog	Buffered version of cerr	Screen

By default, the standard streams are used to communicate with the console. However, in environments that support I/O redirection (such as DOS, UNIX, and Windows), the standard streams can be redirected to other devices or files.