1.4 Principles of Programming (Paradigms (Procedural - Instructions are…
1.4 Principles of Programming
Procedural - Instructions are carried out linearly. E.g. Python, VB, Java, etc.
Declarative - A set of rules or functions which are called upon when an action is carried out. E.g. Spellcheckers
Event Driven - Programs which respond to actions such as "button clicked". E.g. VB
Visual - Where the programmer will manipulate the program visually. E.g. Scratch
Mark-Up - Describes how text, images and other content are displayed on a GUI. E.g. HTML
Object Oriented Programming - Where a base "class" is created and is given attributes and methods. From this template, "Objects" can be created, which inherit some of the attributes, but may have completely different methods.
Low level - Languages of this type refer to specific memory locations and are highly specialised. They allow the user to interact with components like the CPU and registers directly. Eg. Machine code and assembly language
High level - Allows the use of variables and data structures such as lists, among many other things. These languages are built on the foundations of low level languages, so one process carried out translates to multiple low level instructions. Eg. Python, VB, Java
1GL - Handles very basic processes at extremely high speeds, as it is read directly by the CPU. There are no compilers or assemblers and the code is written in binary. Eg. Machine code
2GL - This level of code can be read by a programmer, by must be converted to machine code through assembly. Eg. Assembly language
3GL - The most commonly used and basic generation of languages, 3GLs are easy to learn and give the ability for the user to create complex systems. They are much more user friendly, usually offering detailed error messages and online resources and libraries. Eg. VB, Python, Java
4GL - Languages that are designed to be more user friendly and more specialised than 3GLs. They are often created to handle a specific area of computer programming. Eg. Graphical, Mathematical and Fluid representation programs.
BNF - A standard for explaining the grammar of a programming language.
Eg. <name> ::= <letter>
Eg. <letter> ::= "a"|"b"|"c"|...|"z"
Recursion eg. <number> ::= <digit>|<digit><number>
BNF explained in a diagram
Circles for characters and symbols. Eg. "a" or 1
Rectangles for "variables" which link to other diagrams
Recursion is done by an arrow pointing back around
Eg. Username = -> FirstName -> "." -> LastName -> Digit ->
Standards - In computer programming, standards are used so that manufacturers don't create devices that are incompatible with each other. Eg. USB (Universal Serial Bus)
Machine Code - Binary code which a computer can interpret and execute.
Assembly code - Works in mnemonics (eg. ADD) and references memory locations, similar to machine code but a bit more user friendly.
Source code - Code written in high level languages, near to English and is much easier to interpret.