Wisnu Anggoro - Learning C++ Functional Programming: Metaprogramming, Concurrency, Lazy Evaluation, and more

BIRMINGHAM - MUMBAI

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First published: August 2017

Production reference: 1080817

ISBN 978-1-78728-197-4

www.packtpub.com

Wisnu Anggoro is a Microsoft Certified Professional in C# programming and an experienced C/C++ developer. He has also authored the books Boost.Asio C++ Network Programming - Second Edition and Functional C# by Packt. He has been programming since he was in junior high school, which was about 20 years ago, and started developing computer applications using the BASIC programming language in the MS-DOS environment. He has solid experience in smart card programming, as well as desktop and web application programming, including designing, developing, and supporting the use of applications for SIM Card Operating System Porting, personalization, PC/SC communication, and other smart card applications that require the use of C# and C/C++. He is currently a senior smart card software engineer at CIPTA, an Indonesian company that specializes in innovation and technology for smart cards. He can be reached through his email at wisnu@anggoro.net.

Aivars Kalvans holds the position of Lead Software Architect at Tieto Latvia. He has been working on the Card Suite payment card system for more than 15 years and maintains many core C++ libraries and programs. He is also responsible for the C++ programming guidelines, secure coding training, and code reviews, and he organizes and speaks at internal C++ developer meetups as well.

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Functional programming is a style of constructing the elements and structure of a computer program by composing pure functions, avoiding shared state, mutable data, and side-effects, like we usually see in mathematics. The variable in the code function represents the value of the function parameter, and it is similar to the mathematical function. The idea is that a programmer defines the functions that contain the expression, definition, and the parameters that can be expressed by a variable to solve problems.
Functional programming is declarative rather than imperative, which means programming is done with expressions or declarations instead of statements. The application state of functional programming flows through pure functions, so it avoids the side effect. In contrast to imperative programming, the application state is usually shared and collocated with methods in objects. In imperative programming, the expressions are evaluated, and the resulting value is assigned to variables. For instance, when we group a series of expressions into a function, the resulting value depends upon the state of variables at that point in time. Because of the continuous changes in state, the order of evaluation matters. In functional programming, destructive assignment is forbidden, and each time an assignment happens, a new variable is induced. Best of all, functional code tends to be more concise and predictable, and easier to test than imperative or object-oriented code.