What is Programming Paradigms? Imperative vs Declarative Programming Paradigms 4 Major Programming Paradigms - Imperative (Procedural, Object-Oriented) - Declarative (Logical, Functional) Procedural Programming Paradigm Logical Programming Paradigm Functional Programming Paradigm Object Oriented Programming Paradigm

1. MAJOR PROGRAMMING
PARADIGMS
MUHAMMED ASIM YILDIZ

2. Inside
 What is Programming Paradigms?
 Imperative vs Declarative Programming Paradigms
 4 Major Programming Paradigms
 Procedural Programming Paradigm
 Logical Programming Paradigm
 Functional Programming Paradigm
 Object Oriented Programming Paradigm

3. Programming Paradigm
 Is an approach to programming a computer;
 Based on mathematical theory or
 A coherent set of principles

4. Imperative – Declarative Programming
Paradigms
 Question :
 I’m right next to Eagle Statue. How do I get to Digiturk from here?
 How can we define it with Imperative PP?
 How can we define it with Declarative PP?

5. Imperative Way
 Head east on Mumcu Bakkal Sokağı toward Şht. Asım Cd.
 Turn left onto Şht. Asım Cd.
 Continue onto Masuklar Ykş. (110m)
 Continue onto Yıldız Cd. (270m)
 Digiturk is on the right

6. Declarative Way
 Digiturk’s address is Cihannüma, Yıldız Cd., 34353 Beşiktaş/İstanbul

7. Imperative programming is like how you do something,
while declarative programming is more like what you do.

8. Another Example
 You go to a restaurant and approach the front desk
 If you say :
 I see that table located under the TV is empty
 I would like to sit there
 IMPERATIVE (define how to get a table)
 Or if you say :
 Table for one, please
 DECLARATIVE (what you want)

9. Many (if not all) declarative approaches
have some sort of underlying imperative abstraction.

10. Imperative-Declarative Relation
 The declarative response for restaurant assumes that the front-desk guy knows..
 Knowing the Digiturk address assumes you have a some sort of GPS that knows..
 ‘THE IMPERATIVE STEPS’

11. Examples of PP with
Programming Languages
 SQL :
 HTML :
<article>
<header>
<h1>Declarative Programming</h1>
<p>Sprinkle Declarative in your verbiage to sound smart</p>
</header>
</article>
SELECT * FROM Users WHERE Country=’Mexico’;

12. Examples of PP with
Programming Languages
 Javascript (write a function called double which takes an array, and return a new array where
the values doubled) :
function double (arr) {
let results = []
for (let i = 0; i < arr.length; i++){
results.push(arr[i] * 2)
}
return results
}
function double (arr) {
return arr.map((item) => item * 2)
}

13. Programming Languages by Paradigms
 Imperative: C, C++, Java
 Declarative: SQL, HTML
 (Can Be) Mix: JavaScript, C#, Python

14. 4 Major Programming Paradigms
 Imperative
 Procedural
 Object-Oriented
 Declarative
 Logical
 Functional

15. IMPERATIVE PROGRAMMING PARADIGMS

16. Procedural Programming Paradigm
 The entire program is a single algorithm consists of independent modules
 The complete functionality written linearly (step-by-step)

17. Procedural PP Example

18. Procedural PP Advantages
 Efficient (modules are easier to write)
 Close to the machine
 Best for expressing algorithms

19. Procedural PP Disadvantages
 The semantics of the program can be complex
 Hard to understand and hard to prove (lots of modules)
 Side effects make debugging harder
 Order is crucial (step-by-step)

20. Object Oriented Programming Paradigm
 Real-world objects are each viewed as seperate entities
 Each object has it’s own state which is modified only by built in methods
 Objects operated independently (communication is done by message passing)

21. OOP PP Example

22. OOP PP Advantages
 Inheritance (reusable code and code extensibility)
 Changing code without the need to change existing code (subclass)
 Encapsulation and information hiding
 Prevents data from being accessed by the code outside
 Define data as private and open them to outside by public methods
 Parallel code development with big teams
 More human-friendly and readable code

23. OOP PP Disadvantages
 First time coding can be more extensive (code duplication)
 Can create a massive amount of unnecessary code
 Can be slow because of the overhead (negligible)

24. DECLARATIVE PROGRAMMING PARADIGMS

25. Logical Programming Paradigm
 Execution of a logic program is a theorem proving process (Datalog, Prolog)
 Program statements express facts, rules and predicates
 It consists from a system of formal logic

26. Logical PP Example
 Given information about fatherhood and motherhood, determine grand parent relationship :
 Given the information called facts;
 John is father of Lily – father(john, lily)
 Kathy is mother of Lily – mother(kathy, lily)
 Lily is mother of Bill – mother(lily, bill)
 Ken is father of Karen – father(ken, karen)
 Who are grand parents of Bill?
 grandparent(X,Z) :- parent(X,Y), parent(Y,Z)
 parent(X,Y) :-father(X,Y)
 parent(X,Y) :-mother(X,Y).

27. Logical PP Advantages
 The system solves the problem
 Programming steps are kept to a minimum
 Proving the validity of the program is simple

28. Logical PP Disadvantages
 Not efficient as other programming paradigms
 Takes too much effort to create a program
 Not widely used (medical diagnosis, robot control etc.)

29. Functional Programming Paradigm
 Views all subprograms as functions (in mathematical sense)
 Functions take in arguments and return a single solution
 Solution returned is based entirely on the input
 The time which a function is called has no revelance

30. Functional PP Example

31. Functional PP Advantages
 High level of abstraction
 Functions suppress many of the programming details
 Removes the possibility of making too many errors (simple)
 Good candidates for programming to parallel computers

32. Functional PP Disadvantages
 Problems involving many variables or
 Problems with a lot of sequential code runs;
 Sometimes easier to implement with Object oriented programming

33. THANK YOU