1.4 Programming

Question 1

Class definition

Answer 1

A class is a set of objects which share a common data structure and current behaviour. 
It is the template that can be used to create objects

Question 2

An object definition

Answer 2

An object is an instance of a class when they’re being used

Question 3

Instantiation definition

Answer 3

Is it the concept of an object to being based on a class

Question 4

Encapsulation definition

Answer 4

Objects should contain within themselves everything I need including all the attributes and methods

Question 5

Polymorphism definition

Answer 5

The same name is used in the class hierarchy for a method but each class may implement this method to differently

Question 6

Inheritance definition

Answer 6

Enables new objects to take on the properties of existing objects
Super class is used as the basis for inheritance

Question 7

Subclass

Answer 7

Is that in Heritance from a super class is called asset class. Inheritance in different relationships between classes and organises classes into groups

Question 8

State the purpose of Backus-Naur form (BNF

Answer 8

BNF is used to describe (unambiguously) the syntax/grammar of a programming/computer language.

Question 9

why Backus-Naur Form (BNF) is preferable to ordinary English or Welsh when defining the syntax of a computer language

Answer 9

It is unambiguous

Question 10

Explain the difference between a procedural and non-procedural programming language

Answer 10

Procedural languages are concerned with carrying out an ordered set of instructions
Non-procedural languages are to do with facts / rules / queries

Question 11

4GL

Answer 11

· used in (e.g.) a relational database system as a query / manipulation language
Why:
· aimed at end-users / relatively close to natural language / requires less programming skill.

Question 12

Visual Language

Answer 12

· used for production of objects / buttons / icons / GUI / Windows / graphics content / event driven environment.

Why:
· may be easier to learn / more intuitive because visual / good help / tools available

Question 13

State when a scripting language might be used

Answer 13

A scripting language is often embedded in other languages and can add functionality to web pages

Question 14

Explain why careful version control is necessary when developing computer programs

Answer 14

· If programmer A modifies current version, and programmer B modifies an earlier version, neither new version will contain both modifications
· Any amendments must be made to the most recent versions.

Question 15

Explain the role of a break point when debugging a program

Answer 15

Break point: allows the programmer temporarily to halt execution in order to ascertain the value of variables at that point

Question 16

Explain the role of a variable watch when debugging a program

Answer 16

Variable watch: lists the value of a variable at specific points during the execution.

Question 17

Explain the role of a store dump when debugging a program

Answer 17

Store dump: lists the entire contents of memory at a specific point.

Question 18

Explain what is meant by the term parallel processing

Answer 18

Parallel processing is the simultaneous use of several processors / cores to perform a single task.

Question 19

give an example of an application where parallel processing might be useful.

Answer 19

PP could be useful in (for instance) weather forecasting or image processing

Question 20

Discuss the nature of different programming paradigms

13 marks

Answer 20

Procedural languages
· Procedural languages are used in traditional programming based on algorithms or a logical step by- step process for solving a problem
· Allows tight control over the underlying operation of the hardware
Scripting Language
· Set of commands understood by the applications software
· Usually embedded in another language and is used to control aspects of the software
Non-Procedural languages
· Non-procedural programming languages allow programmers to specify the results they want without specifying how to solve the problem
· Non-procedural languages are to do with rules / making queries
Object Orientated Language
· Uses objects and classes - include both data and associated processing
· Applies the principles of encapsulation, inheritance and polymorphism to aid programming
Special Purpose Language
· Languages that were designed with a specific purpose in mind as opposed to a more general use language
· Might have essential / helpful features relevant to the application
4th Generation Language
· First generation programming languages created construct above the machine-code program
· Each subsequent generation represented a further distancing from the binary code that the computer hardware actually reads
Natural Languages
· The user would not need to structure voice (or typed) input in any way - could communicate with the computer as if with another person
· A natural language interface would need very high processing power / very complex software
Visual Programming Languages
· High level programming language
· Particularly suitable for production of objects / buttons/ icons, etc.
Application packages that have programming
capabilities
· Additional functionality can be added without a programmer / buying another package / program
· Can customise the package / tailor to specific needs etc