Programming Paradigms

A brief introduction to programming paradigms and how to use them.

Transcript

1. PROGRAMMING Paradigms
2. Programming paradigms define the style and approach by which we build software.
3. It is the way of programming.
4. STRUCTURED DECLARATIVE IMPERATIVE PARADIGMS PROGRAMMING Examples of Common PARALLEL PROGRAMMING • Express the intent of programs through logical steps • Specify what is computed, not how • Functional programming (based on mathematical functions) • Higher-order functions for composition and reduction • Abstract data types, inheritance, polymorphism • Improve the clarity of programs through block structures and subroutines. • Model the "real-world" • Object-oriented programming • Class-based vs. prototype based • Programs written for parallel computation • Distributed computing across processors (CPU and GPU) • Message passing, actor model • States, sequences and assignments • Define sequences of commands to accomplish tasks • Procedural programming
5. DECLARATIVE ! var arr = [1, 2, 3, 4, 5] ! var total = arr.reduce(function(sum, x) { return sum + x ! }) ! return total
6. ! int arr[] = [1, 2, 3, 4, 5] ! ! int total = 0; for (int i = 0 ; i < arr.length ; i++) { total += arr[i]; } ! return total; IMPERATIVE
7. STRUCTURED ! ! public class ValHolder extends Object { public int sum(int[] intArray) { int total = 0; for (int i = 0; i++; i < intArray.length) { total += intArray[i]; } return total; } } ! public static void main(String args[]) { ValHolder vh = new ValHolder(); System.out.println(vh.sum(new int[]{1, 2, 3, 4})) } ! !
8. ! ! import scala.actors.Actor import scala.actors.Actor._ case class Inc(amount: Int) case class Value class Counter extends Actor { var counter: Int = 0; def act() = { while (true) { receive { case Inc(amount) => counter += amount case Value => println("Value is "+counter) exit() } } } } object ActorTest extends Application { val counter = new Counter counter.start() for (i <- 0 until 100000) { counter ! Inc(1) } counter ! Value // Output: Value is 100000 } PARALLEL PROGRAMMING
9. Certain languages support multiple paradigms, while others were designed specifically for a few.
10. STRUCTURED DECLARATIVE IMPERATIVE PARADIGMS PROGRAMMING Examples of Common PARALLEL PROGRAMMING • Functional languages • Scala, Haskell, Clojure, Python • Logic Programming • Prolog • Domain-specific • SQL, Markdown, HTML • Object-oriented • Smalltalk, Java, JavaScript, C# • Ruby, Python, PHP • Scala, C++ • Actor Model • Smalltalk, Scala (Akka) • Multi-threaded • Go, Clojure, Java, C++ • Procedural • FORTRAN, Pascal, Cobol • Python, PHP, Prolog • Go, C, C++, Lisp
11. You may end up employing more than one paradigm in building a large system.
12. But some paradigms do not work well together .
14. So which one do we use?
16. What problem are you trying to solve?
17. Solving a programming problem requires choosing the right concepts.
18. Are you building a web application?
21. Just because you can do something, does not mean you should.
23. Are you building a micro-services platform?
25. In the end, you may end up using more than one to build a complete solution.
26. What's Next • Reactive programming • Fault tolerant • Actor Model
27. Thank you