Explain High Level Languages (IC T1 Q20)

High level languages are programming languages that are easier for humans to write programs in than the computer’s own language, machine code. Some high level languages are better than others for writing programs for specific tasks, such as:

·         creating games

·         controlling robots

·         mathematical solutions

Common features of high level languages

All high level languages:

·         look a little like English

·         must be translated into binary before they can be run

·         are intended to help the programmer solve problems

·         are easier to edit than machine code

Examples you may know:

·         C++

·         Visual Basic

·         Pascal

·         Comal

·         Prolog

The need for translation

General

A translator changes a computer program from a high level language to machine code.

By loading different translator programs, a computer can seem to "understand" different high level languages such as BASIC and Pascal.

Translator programs are a very important part of the computer's systems software.

There are two different types of translator program, interpreters and compilers.

·         An interpreter translates the program a line at a time into binary as the program is running.

·         A compiler takes a complete program called the source code and turns it into machine code. The machine code is saved and can be run over and over again.

A table displaying the advantages and disadvantages of the two different types of translator program.

	Advantages	Disadvantages
Interpreter	Syntax and execution errors can be quickly identified.	Relatively slow running because each line of the program must be translated before it can be run.
Compiler	Compiled program runs very quickly.	More difficult to find and fix bugs and errors so it is a more complicated process to write programs.

Portability of software

Credit

If software is described as portable then it can be run on different operating systems (e.g. Mac OS, Linux, PC) with little or no change.

Reasons it may not be portable include:

·         incompatible operating systems.

·         it’s an older computer that isn’t recognising much newer software.

·         the programming language isn’t available for that operating system.

Do not confuse this with hardware portability, which means you can easily carry it around e.g. laptops.

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