Programming Paradigms and Languages Introduction. dr Robert Kowalczyk WMiI UŁ

Transcription

1 Programming Paradigms and Languages Introduction dr Robert Kowalczyk WMiI UŁ

2 What is a programming paradigm? A programming paradigm is a fundamental style of computer programming, a way of building the structure and elements of computer programs. There are two main programming paradigms: imperative programming and declarative programming. source: dr Robert Kowalczyk WMiI UŁ 2

3 Definitions Imperative programming: telling the "machine (computer) how to do something, and as a result what you want to happen will happen. Declarative programming: telling the "machine (computer) what you would like to happen, and let the computer figure out how to do it. dr Robert Kowalczyk WMiI UŁ 3

4 Declarative vs. imperative programming dr Robert Kowalczyk WMiI UŁ 4

5 Imperative vs. declarative programming - example We wish to double all the numbers in an array. Imperative style of programming: var numbers = [1,2,3,4,5] var doubled = [] for(var i = 0; i < numbers.length; i++) { var newnumber = numbers[i] * 2 doubled.push(newnumber) } console.write(doubled) //=> [2,4,6,8,10] Declarative style of programming: var numbers = [1,2,3,4,5] var doubled = numbers.map(function(n) { return n * 2 }) console.log(doubled) //=> [2,4,6,8,10] dr Robert Kowalczyk WMiI UŁ 5

6 Distribution of programming paradygms Programming languages Imperative Declarative Structured Procedural Logical Functional Object-oriented Generic SQL, XML Concurrent dr Robert Kowalczyk WMiI UŁ 6

7 Four main programming paradyms Procedural/Structured programming Object-oriented programming Functional programming Logical programming dr Robert Kowalczyk WMiI UŁ 7

8 Procedural/structured programming Procedural programming is a computer programming language that organised our code into small programs" that use and change our datas. Structured programming is a programming paradigm recommending hierarchical division into blocks of code with one entry point and one or more exit points. In structured programming we use three main structures : - sequences (instruction _1; instruction _2; ; instruction _n), - choices (if, if...else, switch, case), - iterations (while, repeat, for). Key words: variables, types, procedures and abstract datas. Using: network systems, operating systems, etc. Procedural/structured languages: Fortran Cobol Pascal C C++ others. dr Robert Kowalczyk WMiI UŁ 8

9 Procedural/structural programming - example dr Robert Kowalczyk, Katedra Analizy Nieliniowej, WMiI UŁ 9

10 Object-oriented programming Object-oriented programming is a programming paradigm in which programs are defined using objects - the state of the connecting elements (or fields) and behavior (or method). Object-oriented computer program is expressed as a set of such objects, which communicate with each other in order to perform tasks. Key words: classes and objects, inheritance, encapsulation, polymorphism. Using: www and stand-alone applications. Object-oriented languages Simula, Smalltalk, C++, C#, Java, others. dr Robert Kowalczyk WMiI UŁ 10

11 Obcject-oriented programming - example dr Robert Kowalczyk WMiI UŁ 11

12 Functional programming Functional programming is a programming paradigm in which the functions are the core values and the emphasis is on valuation (often recursive) function, and not to execute commands. Theoretical basis for functional programming was developed in the 30thTwentieth century by Alonzo Church's lambda calculus, namely lambda calculus with types. Key words: functions, lambda calculus, parametric polymorphism. Using: theoretical, in telecommunications, in financial calculations. Functional languages: Lisp, ML, Haskell, H#, Erlang others. dr Robert Kowalczyk WMiI UŁ 12

13 Functional programming - example dr Robert Kowalczyk WMiI UŁ 13

14 Functional programming - example dr Robert Kowalczyk, Katedra Analizy Nieliniowej, WMiI UŁ 14

15 Logical programming The paradigm of logic programming is a programming method in which the program is given as a set of relations, and the relationship between these dependencies. Key words: facts, reports, queries. Using: theoretical, artificial intelligence. Logical languages: Gödel, Fril, Prolog, others. dr Robert Kowalczyk WMiI UŁ 15

16 Logical programming - example dr Robert Kowalczyk, Katedra Analizy Nieliniowej, WMiI UŁ 16

17 Logical programming - example dr Robert Kowalczyk, Katedra Analizy Nieliniowej, WMiI UŁ 17

18 TIOBE index popularity of programming languages źródło: dr Robert Kowalczyk, Katedra Analizy Nieliniowej, WMiI UŁ 18

19 C/C++ (schedule) Introduction to the course (18th February) dr Robert Kowalczyk WMiI UŁ 19

20 Haskell (schedule) Starting out (me) ( ) Types and Typeclasses + Syntax in Functions (student) ( ) Maysoon Hussien Ali Recursion + higher order functions (student) ( ) Besart Vishesella and Ysee Monnier Modules + Input/Output (student) ( ) Urte Zubkaite Revision Haskell language (student) ( ) Mothefer Jahefer, Nika Tsogiaidze Haskell test ( ) We refer the chapters of the book Learn You a Haskell for Great Good! By Miron Lipovaca dr Robert Kowalczyk WMiI UŁ 20

21 Prolog (schedule) Introducing Prolog (me) ( ) Tutorial Introduction and A Closer Look (student) ( ) Andriy Byalyk, Tokenova Madina Using Data Structures and Backtracking and the Cut (student) ( ) Dmitrii Mitroshenkov Input and Output and Built-in Predicates (student) ( ) Chowdhury Joy Barua Revision Prolog language (student) ( ) Fatih Burak Ustun Prolog test ( ) We refer the chapters of the book Programming in Prolog by William Clocksin, Christopher S. Mellish dr Robert Kowalczyk WMiI UŁ 21

22 Exam Exam term 0 ( ) dr Robert Kowalczyk WMiI UŁ 22

23 How to get course credit To pass the class: 1 lecture + 2 tests (Haskell+Prolog) To pass the lecture: Exam = 15 close questions and 5 open questions dr Robert Kowalczyk WMiI UŁ 23

24 Main rules for classes and lectures Pass classes: lecture plus two tests Pass lectures: exam My website: My office room: A327 My work hours: Wednesday 2pm-4m 1 class introduction 1 class my Haskell lecture 3 classes students Haskell lectures 1 class revision to prapere for the Haskell test 1 class the Haskell test 1 class my Prolog lecture 3 classes students Prolog lectures 1 class revision to prapere for the Prolog test 1 class the Prolog test 1 class - exam dr Robert Kowalczyk WMiI UŁ 24

25 Literature Learn You a Haskell for Great Good! by Miron Lipovaca Programming in Prolog by William Clocksin, Christopher S. Mellish Any www sites and books dedicated to Haskell and Prolog languages dr Robert Kowalczyk WMiI UŁ 25

26 Any Quetions? dr Robert Kowalczyk WMiI UŁ 26