1. High or Low Level Programming Language? Justify your decision.
Machine
Java
Python
Scratch
Assembly

2. High/Low Languages & Language Translators
4.5.1
4.5.2

3. Learning Objectives
4.5.1 Understand what is meant by high-level and low-level programming languages and assess their suitability for a particular task
4.5.2 Understand what is meant by a compiler and an interpreter
Online worksheet for this lesson

4. High/Low Languages
4.5.1

5. Check Java Python Scratch Assembly Machine High Level Languages
Low Level
Languages
Machine

6. 10 min
Your Turn: Take Notes
Watch this video about high and low level programming languages
Take notes in a table like this:
High Level
Low Level
Task 1: On class worksheet

7. Characteristics Check Scratch Python Java Assembly Machine
Works on many different microprocessors (machine independent)
Commands look similar to English language
Easier for humans to read/understand than assembly or machine code
Scratch
Easy and quick for humans to write and maintain code
High Level
Languages
Python
Java
Needs to be translated to machine code
Low Level
Languages
Each statement is exactly one instruction in machine code
Use mnemonics (abbreviations)
Only works on one type of microprocessor (machine dependent)
Each instruction has an opcode and operands
Assembly
Needs to be translated to machine code
Machine
0s and 1s only
No translator needed
Directly executable by machine
Only works on one type of microprocessor (machine dependent)
Difficult for humans to read

8. Your Turn: Justify Usage
5 min
Your Turn: Justify Usage
Why would you want to use each either a high or low level language?
Task 2 on class worksheet
We’ll check your answers with the next slide
Task 2: On class worksheet

9. Why Use Each? Check Python Java Assembly Machine
May have built-in libraries of useful functions already written and tested.
Commands look similar to English language, so it’s easy and quick for humans to write and maintain code
Code can be written once and ported to many platforms (Windows, LINUX)
High Level
Languages
Python
Java
Easy and quick for humans to write and maintain code
Low Level
Languages
It’s a very good way to control hardware, like printers or graphics cards.
Sometimes, it’s the only language available. For example, a new chip is invented.
Sometimes, the function needed is not available in a high-level language.
Can be used to speed up parts of high-level language programs.
Each statement is exactly one instruction in machine code, so it’s very efficient.
Assembly
Machine
Almost no one writes machine code now.

10. Questions?
That finishes ‘high level and low level’ programming languages
Any questions before moving on?

11. Language Translators
4.5.2

12. How does each get translated to machine code?
Scratch
The translator is called an ‘interpreter’.
Python
High Level
Languages
Java
The translator is called a ‘compiler’.
Low Level
Languages
The translator is called an ‘assembler’. It translates from an assembly language to machine code.
Assembly
Machine
No translation necessary. It’s already machine code.

13. Compiler vs Interpreter
10 min
Compiler vs Interpreter
Watch this video about high and low level programming languages
Take notes on the worksheet
We’ll check your answers with the next slide
Interpreter
Compiler
Task 3: On class worksheet

14. Compiler vs Interpreter
Check
Compiler vs Interpreter
Interpreter
Compiler
One line of code is translated and executed at a time; one by one
The interpreter is required for the whole time the program is running
Runs slowly
Can correct mistakes as you go along
Must have interpreter to run code
Very good for prototyping (mocking up)
Python, Scratch
Translates the whole list of instructions in one go
Has some extra processing time in the beginning
The compiler is not needed to execute the translated instructions
Execution of translated code is very fast
Cannot correct mistakes after translation
Don’t need compiler to run resulting code
Java, C, C++

15. Compilers, Interpreters, Assemblers
Assembly
Java
Python
INTERPRETER
Scratch
COMPILER
ASSEMBLER
Low Level
INTERPRETER
High Level
Machine Code

16. Plenary – Make a Choice 2 Assembly Language Interpreter
High Level Language
Compiler
Low Level Language
Machine Language
Needs no translation
Uses mnemonics. Very efficient.
Is not very easy for humans to read or write.
Easy for humans to read and quick for humans to write.
Has to be present for a program to run.
Is not needed to run the translated program. 5 4 6 3 1

17. Homework
Complete this lesson’s homework worksheet
Due in 2 lessons