Language Systems

Question 1

What types are there

Answer 1

Machine Language
Binary coded instructions
Also called object code or machine code
Assembly Language
Symbolic coded instructions
Also called mnemonic codes
High-level Programming Languages
Structured English-like procedural statements with some Mathematical notation
 Script and Markup Languages
More recent, influenced by the Web

Question 2

Assembler

Answer 2

An assembler convert an assembly language program into its machine code equivalent
It translates mnemonic codes to their machine code equivalents
I.e. ADD 200, 216, 220 00010000 0001100…
The assembler also assigns machine addresses (i.e. memory locations) to symbolic labels

Question 3

Compiler

Answer 3

A program that changes high-level language source code to object code that can be executed by the CPU
Compilers do more than just produce object code:
Checks syntax of program
Checks semantics of program
Generates code for target CPU
Primary reason for compiling source code is to create an executable program
Examples of compiler based language:
C, C++, Java

Question 4

Interpreter

Answer 4

An interpreter executes source code instructions written in a high-level programming language but does not produces an executable file
Interpreter:
Checks syntax of program
Takes one instruction at a time and convert it into machine language which is executed before moving on to the next instruction
Examples of interpreter based language:
PHP, JavaScript, BASIC

Question 5

Compiler vs Interpreter

Answer 5

Compiled languages (C, C++) produce executable files that are efficient (i.e. run faster)
Hence their use in computer games
Interpreted languages (Basic, JavaScript, PHP) and hybrids (Java) are notably slower
Interpreted languages and hybrids (Java) are simpler in terms of program development
They tell you where the error is
E.g. Eclipse/Java reports the line were the error occurred

Question 6

Java

Answer 6

Hybrid approach – compiled then interpreted
Introduced in 1996 and swept the computing community by storm
Portability was of primary importance
Java is compiled into a standard machine language called Bytecode
A software interpreter called the JVM (Java Virtual Machine) takes the Bytecode program and executes it

Question 7

C++

Answer 7

A compiled language with a complex compiler
Powerful object-oriented language based on the popular C programming language
Originally called “C with classes”
Widely used in 1990s (until Java came along)
Efficient and complex and suited to many programming applications
Particularly suited to low level and systems programming
Operating systems like windows are written in C++ and C