C++, like C, has no built-in input or output statements. Instead, I/O facilities are provided by a library. The C++ compiler provides both the classic implementation and the ISO standard implementation of the iostream classes.
By default, the classic iostream classes are contained in libiostream. Use libiostream when you have source code that uses the classic iostream classes and you want to compile the source in standard mode. To use the classic iostream facilities in standard mode, include the iostream.h header file and compile using the -library=iostream option.
The standard iostream classes are available only in standard mode, and are contained in the C++ standard library, libCstd.
This chapter provides an introduction to the classic iostream library and provides examples of its use. This chapter does not provide a complete description of the iostream library. See the iostream library man pages for more details. To access the classic iostream man pages type the command: man -s 3CC4 name