Programming Paradigms

What is it?

• A paradigm is simply the way you look at and make sense of the world

• So a programming paradigm is a way of thinking about and expressing a computer program.

• There are quite a few paradigms and some are related

  • Imperative: structured, procedural and object-oriented are examples
    • As a general rule, imperative languages explain how to do something step by step
  • Declarative: functional database (SQL) and mark-up languages (HTML)
    • As a rule, declarative languages describe the problem and the system knows how to deal with it

Structured Programming

• Code that is imperative

  • That is, it defines a series of steps that must be performed to complete a task

• Structured programming is a subset of imperative programming.

• Structured programming sees the world as a sequence of tasks that can be broken down into small, easy to manage chunks

  • These chunks can be reused

Hierarchy or Structure Charts

• A structure chart shows us the calling structure of a program
  • Which subroutines get called from where and what information is passed and returned.

*By Pluke - Own work based on: Structured Chart Example.jpg by ‍Sandia National Laboratories, Public Domain, https://commons.wikimedia.org/w/index.php?curid=16283788 *

Pseudo Code

• Pseudo means not genuine
• Pseudo code allows you to think like a programmer while not needing to worry about the syntax of any given programming language

Finite State Machines

• FSMs allow you to plan the states for a control system and what causes the transition from one state to another and any output.
• A Mealy machine’s outputs are determined by it’s state and input: you label the output on the transition.
• A Moore machine’s outputs are determined only by the current state: the output is labelled in the state.

Comments

• Comments should enhance the readers understanding of the code
• You can assume the reader can already understand code in the language it is written in.
• Avoid in line comments where possible
• Be consistent in terms of comment use
• Comments are especially useful for:
  • Module headers
  • Subroutine headers
  • Explaining the logic behind changes
  • Logging code changes

What is “Object Orientated Programming”?

• Code that is imperative
• Object oriented programming is a subset of imperative programming
• It sees the world as a collection of objects or things
  • You define a generalised example of a thing which includes all the programs and data that it needs to function

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