Abstraction

abstraction is a technique for arranging complexity of computer systems. It works by establishing a level of complexity on which a person interacts with the system, suppressing the more complex details below the current level. The programmer works with an idealized interface (usually well defined) and can add additional levels of functionality that would otherwise be too complex to handle. For example, a programmer writing code that involves numerical operations may not be interested in the way numbers are represented in the underlying hardware (e.g. whether they're 16 bit or 32 bit integers), and where those details have been suppressed it can be said that they were abstracted away, leaving simply numbers with which the programmer can work. In addition, a task of sending an email message across continents would be extremely complex if the programmer had to start with a piece of fiber optic cable and basic hardware components. By using layers of complexity that have been created to abstract away the physical cables and network layout, and presenting the programmer with a virtual data channel, this task is manageable.

Abstraction can apply to control or to data: Control abstraction is the abstraction of actions while data abstraction is that of data structures.

• Control abstraction involves the use of subroutines and control flow abstractions
• Data abstraction allows handling pieces of data in meaningful ways. For example, it is the basic motivation behind the datatype.