Q. How Abstraction used in stepwise refinement?

Abstraction:- Abstraction permits one to concentrate on a problem at some level of generalization without regard to irrelevant low level details employ of abstraction also permits one to work with concepts and terms that are familiar in the problem environment without having to transform them to an unfamiliar structure.

• It permits considering the modules at the abstract level without worrying about its details.
• It offers external behaviour of the modules.
• It is utilized for existing modules as well as for modules that are being design.
• It is necessary for the problem partitioning.