Paradigms

Last updated Aug 6, 2023 Edit Source

• Programming
• Programmingparadigms

Different tasks can be resolved using different methods. Those variants are different programming approaches, called paradigms. We will analize two main paradigms:

• Imperative
• Declarative

Remember that almost all modern languages are multi-paradigm, this means they can implement and combine the capabilities of multiple approaches.

Key points:

• It’s one of the oldest programming paradigms.
• Closely related to machine architecture.
• Focuses on how to achieve the goal.
• Sequence of instructions that must be executed step by step.
• Consists of several statements that produce a result.

For example, you want to display the phrase “Hello, *<username>*!”. How should the program do it ? following these steps:

1. Ask the username
2. Read and remember the username
3. Display the result

This paradigm is divided in three broad categories:

• Procedural Programming Paradigm.
• Object-Oriented Programming.
• Parallel Processing Approach.

Procedural Programming

• Paradigm where the program is written as a collection of classes.
• Each class has instances (also called objects).
• Class: Way of describing an entity in general, defining usual state, behavior, rules for interacting with it. Its viewed as a set of data (with fields, attributes, class members and functions like methods for working with them)
• It can handle all kinds of common real-life problems.

Programming languages with Object-Oriented Programming:

• Java.
• C++.
• Python.
• Simula.
• Smalltalk.
• Visual Basic .NET.
• Objective-C.

• Helps reduce instructions execution time.
• Shares and/or parallelizes instructions across multiple processors.
• “Divide and conquer”

Programming Languages with Parallel Processing Approach:

• NESL.
• C.
• C++.

• Specify the problem and the expected result.
• Answers with “What needs to be done?” and “What will be the result of the work?”.
• You tell the system what you need and let it try to come up with a solution

This paradigm is divided in three categories:

• Logic Programming Paradigm.
• Functional Programming Paradigm.
• Database Paradigm.

• Heavily based on formal logic
• Set of sentences in a logical form that express facts and rules

Basic statements of logic programming are:

• Facts. Fundamental assertions about the problem domain (“Socrtates is a man”).
• Rules. Interferences about the facts in the domain (“All men are mortal”).
• Queries. Questions about that domain (“Is Socrates mortal?”)

The task here is to find the answer to the query based on facts and rules.

Programming languages with Logic Programming Paradigm:

• Prolog.
• ASP.
• Datalog

• The computation process is interpreted as the computation of the values of functions.
• The function is similar to a mathematical function.
• The function input is an array that is not changed.
• The function output is a new array with new data.
• Function is different from a function in Procedural Programming, where the function is a sequence of actions that change the original data.

Example: You might have a function that takes a list of numbers as input and returns a new list with the squares of those numbers. This does not change the original list of numbers

Programming Languages with Functional Programming Paradigm:

• JavaScript.
• Haskell.
• Scala.
• Erlang.
• Lisp.
• ML.
• Clojure.
• OCaml.
• Common Lisp.
• F#.

• Based on working with data.
• The data is stored in the database.
• Queries are made to the database in a special language (like SQL).
• Special languages let you access the data.
• You can filter, transform, calculate statistics, and so on on this data.
• Program stattements are data-defined rather than a hard-coded series of steps.

The database program is the heart of the business information system, allowing for file creation, data entry, updating, querying and reporting functions.

• Different approaches to creating programs are called paradigms.
• There are two main Programming Paradigms: Imperative and Declarative
• Imperative Paradigm focuses on achieving a result using step-by-step instructions that change data sequentially.
• Imperative Paradigm includes: Procedural Programming Paradigm, Object-Oriented Programming and Parallel Processing Approach.
• Declarative Paradigm focuses on the task and tries tog et an expected result.
• Declarative Paradigm includes: Logic Programming Paradigm, Functional Programming Paradigm, and Database Programming Paradigm.