Programming Languages Revision A Level Computer Science High

Programming Languages Revision A Level Computer Science

High Level Languages • Higher Level Language • Compilation or Interpretation • Processor Independent – Run on a variety of platforms

Low Level Languages • • Assembly Language Use mnemonics Instruction Set Access memory and registers directly Machine Code Pure binary Processor Dependent Each processor has its own different instruction set

Compiler • A compiler translates the whole program as a unit. • Creates an executable program that is portable • Protects program from malicious use. • Source code not available • Compiler/IDE no longer needed once executable is produced. • Makes the software portable

Interpreter • An interpreter translates one line of code then allows it to be run before translation of next line. • Reports one error at a time then stops and indicates position of error. • Programs executes more slowly due to translation. • Helpful during coding development as can debug programs easily. • Java. Script is interpreted by the web browser when executed

What is Java. Script? • Higher Level Language • Interpreted by the web browser when executed NOT compiled • Runs on many platforms • Runs in a web browser that can be embedded into HTML with <script> tag to add interactivity to a page. • Can be either embedded within HTML file or run as an external script (similar to CSS files). • Client Side Processing – Reduces pressure on servers • Online Forms • Security issues – can be amended/circumvented

What is Python? • • Higher Level Language Compiled Produces portable executable file No other software required to run the executable • Executable cannot be un-compiled – source code not available