1. ND Unit 06
Types of Programming Language

2. This session will cover:
 Procedural languages
 Object-orientated programming
 Visual languages
 Mark-up languages
 Scripting languages
 To Pass assignment 1 you must describe 4
different types of language [P1]

3. Procedural Languages
 Early Windows programs used these
 The program controls what happens not the
user
 The task is completed based on user input
 Tasks are broken into a number of stages
known as procedures or subroutines

4. Procedural Languages
 Each procedure does a specific part of
the task
 For example a procedure might open a
file, read in a number or multiply 2
numbers
 Examples are C, Fortran, Pascal, and
Basic

5. Object-orientated programming (OOP)
 Is relatively new and not used until the
1990’s when programs got more complex
 The program is broken down into objects, not
lists of instructions
 Each object can perform tasks and
communicate with other objects
 The object can be thought of as a small
machine with a set job

6. Object-orientated Example
 A company’s personnel records program
would have an employee object
 The employee object would have features
such as Forename Surname and date of birth
– we call these attributes
 The object would also have actions such as
join company, leave company, change details
– we call these methods

7. Object-orientated programming (OOP)
 Unlike procedural programming, the
programmer does not need to know the code
which is ‘behind’ each object making it work
 They only need to know the attributes and
methods of each object and how to make it
interact with other objects
 They then use the objects as ‘building blocks’
to make the program do what they want it to
 Examples languages capable of OO are
Java, C# and VB.NET

8. Visual Programming Languages
 These are used to create software
which has a graphical user interface
(GUI), such as Windows programs
 VP languages have procedural features
but also have OO capabilities
 Examples of VP languages are Visual
Basic.NET and Visual C++

9. Visual Programming Languages
 VP design has 2 stages
 First the programmer
designs the GUI, placing
objects such as
textboxes, buttons and
labels onto a form
 Then they write the code
which gives the
functionality to the
program

10. Markup Languages
 A markup language combines text and
extra information about the text
 This extra information is in the form of tags
 Tags control the structure or presentation of
the text – should it be large or small
font, blue, green, bold or underlined?
 The programmer can also insert
images, hyperlinks and tables into the text
using tags

11. Markup Languages
 The best-known markup example is Hypertext
Markup Language (HTML), used on the World
Wide Web
 Example:
<title>Home Page</title>
<style type="text/css" media="screen">
@import "stylesheets/public.css";
body { background-color: white };
</style>
 Another example is XML (Extensible Markup
Language) which allows users to write their
own tags

12. Scripting languages
 Scripting languages can be typed in directly
from a keyboard
 Some are used to execute a series of
commands that would otherwise have to be
typed in via a keyboard / mouse
 These can be used to control the operating
system and are known as a shell script
language
 Examples are VBScript and Windows
Powershell

13. Scripting languages
 Others allow users to write
short, simple, programs
 Often the language used is specific to each
application such as the macro languages
used in Access or Excel
 Script can also be used to write functions that
are included in HTML pages to do tasks which
can’t be done with HTML alone
 An example of this is JavaScript

14. Which language to use depends on:
 Organisational policy – your company may be
‘tied’ to Microsoft or Macintosh
 Will it work on the hardware already used?
 Does it do what we need it to?
 Are current staff trained in its use?
 Is it reliable? Important for safety-critical
systems!
 Costs of developing and maintaining programs
 Will it be expandable in future?