4.6.2 Classification of Programming Languages

Why were low-level languages written?

The limited speed and memory of early computers

- Directly manipulated the processor

- Required a great deal of effort

- Prone to errors

What are the types of low level language?

- Machine code

- Assembly language

What is machine code?

Code that directly manipulates the processor

→ Only uses 1s and 0s to represent instructions

What makes up machine code?

- Opcode (instruction)

- Operand (data used to carry out the instruction

What are the advantages of using machine code?

- Very powerful due to its direct manipulation

- No need to translate

What are the disadvantages of using machine code?

- Very long

- Difficult to read and understand

- Prone to errors

- Difficult to debug

What is machine code suited to?

Embedded systems

- Low processing power

- Speed of execution is important

What is assembly language?

Language that makes use of mnemonics in place of binary instructions

What are the advantages of using assembly language?

- More compact

- Less error-prone

- 1-to-1 correlation to machine code

What is a high-level language?

A programming language that is close to human speech

→ e.g. Python

What are the advantages of using high level languages?

- Easier to learn and understand

- Easier to debug

- Not platform specific

What are the disadvantages of high-level languages?

- Must be translated into machine code before use

- Object code may run slower

- Cannot manipulate individual bits

What makes high-level programming easier to debug?

- Named variables

- Indentation

- Commenting

- In-built functions

What is an imperative language?

Focus on how a problem should be solved

→ Requires step-by-step instructions

What is a declarative programming language?

Focus on what needs to be done, rather than how to do it