Functional/Sequential/Procedural/Imperative/Declarative Programming

❤️ Imperative 명령형

🆚 Declarative
focus more on how

• Procedural Programming
• OOP

💙 Declarative 선언형

🆚 Imperative
program by expressing logic of computation withoug talking about control flow
focus more on what needs to be done than how
declare the result we want

• Logic Programming
• Functional Programming
• Database

❤️ Procedural Programming 절차 지향

procedures that perform specific tasks
sequence, steps, procedure
focuses on the order of procedures

• if order changes, the result will change
• 👍🏻 similar to computer operation, fast in running
• C, Pascal, Fortran

❤️ OOP 객체 지향

object: instance of class
organize code around object and their interaction

• Encapsulation, Abstaction, Inheritence, Polymorphism
• 👎🏻 slower than procedual programming
• Java, C++, Python, Ruby

💡 https://soheeparklee.github.io/posts/cs-4OOP/

❤️ Parallel Processing

• program instructions by dividing them among multiple processors

💙 Logic Programming

abstract model of computation
knowledge and problem to solve

💙 Functional Programming

mathematical functions
pure functions: don’t alter state or rely on external state

• Pure functions
  • more than one pararmeter
  • no variable other than parameter
• Function composition
• Avoid shared state
• Avoid mutating state

• Avoid side effects

• Haskell, Scala, functional features in Python and JS

var arr = [1, 2, 3, 4, 5];
var map = arr.map(function (x) {
  return x * 2;
}); // [2, 4, 6, 8, 10]

✔️ Functional Programming in JAVA

• lamda
• stream api
• functional interface

✅ Sequential Programming

linear execution of instructions
each statement is executed in order

• part of procedural programming

🆚 Procedural Programming

• Procedural programming is a broader paradigm that includes sequential execution
• also involves organizing code into procedures
• include loops and conditionals