It is this standardized version that is covered in the rest of the article. Most of the classes in the library are actually very generalized class templates. Stream manipulators in c++ pdf template can operate on various character types, and even the operations themselves, such as how two characters are compared for equality, can be customized.
The classes in the library could be divided into roughly two categories: abstractions and implementations. Classes, that fall into abstractions category, provide an interface which is sufficient for working with any type of a stream. The code using such classes doesn’t depend on the exact location the data is read from or is written to. For example, such code could write data to a file, a memory buffer or a web socket without a recompilation. The implementation classes inherit the abstraction classes and provide an implementation for concrete type of data source or sink. The library provides implementations only for file-based streams and memory buffer-based streams. The classes in the library could also be divided into two groups by whether it implements low-level or high-level operations.
The classes that deal with low-level stuff are called stream buffers. They operate on characters without providing any formatting functionality. These classes are very rarely used directly. The high-level classes are called streams and provide various formatting capabilities.
They are built on top of stream buffers. The following table lists and categorizes all classes provided by the input-output library. The directions of the bit-shift operators make it seem as though data is flowing towards the output stream or flowing away from the input stream. This program would output “Hello, world!