Information & Communication Technology 1996-2003

GCSE Revision


Computer Software - Programming Languages

A programming language is used to write all computer programs. A program is simply a list of instructions stored in the computer's memory or on some form of storage media. Any language needs to be understood by both humans and computer. Examples: Visual Basic, C++, Java, Pascal, HTML, Logo.

(You are only required to have a brief outline awareness of the following material at GCSE level. Much of the detailed content provided here is to help you piece together computer terms you may have picked up but have little understanding of.)


Logo  is very simple computer language for giving instructions to a computer. It is usually used to draw shapes on the computer screen or to move a motorised buggy or "turtle" around the floor, e.g.
REPEAT 4 [RIGHT 90 FORWARD 5]
(Just follow the commands by stepping forward 5 paces and turning right 90 degrees, then repeat this 4 times and you will end up moving in a square.)

**Most GCSE exam papers include a question using or interpreting simple Logo commands**

HyperText Markup Language (HTML) (not required for GCSE) is a very different, but still quite simple, language for telling the computer how to display text and pictures on the screen. It is used by all Internet browsers to communicate with each other via the telephone line, e.g. the following will put some bold text and a picture called Image1.gif on the screen:
<b>A picture of me</b> <img src="Image1.gif">
These instructions are saved with .htm or .html added to the end of the filename.

Visual Basic (not required for GCSE) is used to write many of the simpler programs you use on a computer. It is written with a normal text editor using simple (but modified) English commands then 'compiled' into binary number code (00101011) that is faster for the computer to use. The compiled program is saved with .exe added to the end of the filename.

Some application programs, like MS Word, Excel and Access (themselves written using a more advanced programming language) also include a simple Visual Basic editor. This enables the more experienced user to write small programs, called macros, to enhance the functions of these applications even further. For example, the European accent toolbar we have in this school for use in Word uses macros like this one:

Rem Cedilla
CharLeft 1, 1
c$ = Selection$]()
p = InStr("cC", c$)
If (p <> 0) Then
EditClear
Insert Mid("cC", p, 1)
Else
CharRight 1, 1
End If

(This basically moves the cursor and selects the last character typed. If it is the letter c it deletes it and replaces it with a or vice versa.) Fortunately, this is A'level material and only put here to wet your appetite.

 


BackUp Page last updated 30/03/2002 I.D.Lee, Didcot Girls' School
All rights reserved. The original material provided on this site may not be copied or redistributed without written consent but please feel free to add a link to this site from your own website.