Chapter 4

Question 1

Identify the common stages of software
development life cycles (SDLCs).

Answer 1

Feasibility Study, Analysis, Design, Coding, Testing,
Installation, Evaluation and
Maintenance.

Question 2

Define white box testing.

Answer 2

A form of testing carried out by software development teams in which the test plan
is based on the internal structure of the program. All of the possible routes through the program are tested.

Question 3

Define black box testing.

Answer 3

The program as a wh ole is tested from the perspective of the user , it checks all possible user inputs produce valid results.

Question 4

Define Alpha testing

Answer 4

Testing carried out by the software company, in-house. If specifications were not clearly defined by the client, or the client didn’t themselves know what they wanted, issues will be flagged as this stage.

Question 5

Define Beta testing

Answer 5

The program is released to a select few users who will use the program and provide feedback on useability and functionality. Feedback is given to devs.

Question 6

What is TELOS?

Answer 6

A method of analysis used by designers
to evaluate the feasibility of a project. It considers technical, economic, legal and
operational aspects of the project, as
well as scheduling.

Question 7

What are agile methodologies?

Answer 7

A collection of methodologies which aim
to improve the flexibility of software
development. They respond quickly to
changes in user requirements.

Question 8

Describe Waterfall model

Answer 8

It completes the stages in a linear, sequential order.
-Each phase has a well defined start and end
-Each phase has clear criteria for completion
-The company interacts with the client at the start and end, but infrequently during development. Traditional and some what outdated.

Question 9

Pros and cons of waterfall

Answer 9

Pros:
-Simple and easy to mange
-Clearly documented at each stage, so can fixed easily
-Each stage has clear goals

Cons:
-Lack of flexibility
-No risk analysis
-Limited user involvement, only start and end

Question 10

Describe RAD

Answer 10

Rapid Application development: Successive prototypes are produced, shown to the client, evaluated and feedback is used to inform the next iteration. Good features from multiple prototypes can be combined in this process. Small to medium, with unclear requirements.

Question 11

Pros and Cons of RAD

Answer 11

Pros:
-Full project requirement spec not necessary
-Regular client input
-Flexible to changing requirements

Cons:
-Regular client contact; may be impractical
-Many prototypes = expensive
-Poor documentation

Question 12

Describe spiral model

Answer 12

Less riskier version of RAD- more time is spent on planning and risk accessing. Used for large long term projects.

Question 13

Pros and Cons of Spiral model

Answer 13

Pros:
-Focuses on risks, potentially saving lots of time and money
-Good for unclear requirements
-Good for large complex projects

Cons:
-Risk management = specialised: expensive
-Overkill for small projects
-Lack of focus on code efficiency

Question 14

Describe extreme programming

Answer 14

Used for smaller evolving projects.
- Keep the model simple and immediate
- Get rapid feedback from the client
- Keep up-to speed with client’s changing requirements
-Incrementally expand and improve the model over continuous prototyping and iteration. May use pair programming, one codes other gives feedback.

Question 15

Pros and cons of extreme programming

Answer 15

Pros:
-Produces high quality code, fast
-Lots of client involvement
- Requirements can evolve

Cons:
- Pair programming = expensive
-Scope creep - the client may expand on requirements during development
-Client must invest lots of time with devs

Question 16

Key qualities of algorithms

Answer 16

-Inputs must be clearly defined - what is valid and what is invalid?
- Must always produce a valid output for any defined input
- Must be able to deal with invalid inputs
- Must always reach a stopping condition
- Must be well-documented for reference
- Must be well-commented so modifications can easily be made

Question 17

Define programming paradigm

Answer 17

A style of programming or a way organising/ conceptualising a program.

Question 18

What is the low level paradigm

Answer 18

Assembly:
- Uses mnemonics to represent opcodes.
- Hardware dependent
- Runs efficiently, used in embedded systems

Question 19

Define Imperative programming

Answer 19

Imperative programming paradigms use code that clearly specifies the actions to be
performed to dictate how the problem is solved e.g. Python, C.

Question 20

Define Procedural programming

Answer 20

The program can be broken down into subtasks, to modularise the problem. Uses coding constructs of sequence, selection and iteration e.g. Python, C.

Question 21

Define Declarative programming

Answer 21

They tell the computer what to do but not how to do it, e.g. sql queries, haskell

Question 22

Define OOP

Answer 22

Object-Oriented Programming: Instances of objects are created from class templates. Objects are given attributes and methods e.g. Python, Smalltalk

Question 23

Define sequence

Answer 23

Simple, sequential instructions

Question 24

Define selection

Answer 24

A choice/decision AKA condition check where one of two outcomes can be taken.

Question 25

Define iteration

Answer 25

Where code is either iterated definitely or indefinitely.

Question 26

Define subroutines

Answer 26

A named sequence of instructions that can be reused and called from other parts of the program.

Question 27

Define local variables

Answer 27

Exist only within a subroutine. Makes memory use more efficient, cannot be modified outside subroutine.

Question 28

Pros and Cons of coding constructs

Answer 28

Pros:
-Teams can work independently on subroutines
-Local variables make efficient use of memory
-Subroutines can be reused as many times as wanted

Cons:
- Can be hard to keep overview of program of it gets complicated
-Procedural langs harder to model IRL problems and complex GUI’s then OOP langs.

Question 29

Define Inheritance

Answer 29

A class can inherit from another class and this relationship
between classes is shown using the diagram to the right. The subclass (or derived class) will possess all of the methods and
attributes of the superclass (or parent class) and can have its
own additional properties

Question 30

Define Polymorphism

Answer 30

Objects can behave differently depending
on their class. This can result in the same method producing different outputs depending on the object involved. There are two categories of polymorphism: overriding and overloading.

Overriding is redefining a method within a subclass and altering the code so that it functions differently and produces a different output.

Overloading is passing in different parameters into a method

Question 31

Define Encapsulation

Answer 31

Attributes are declared as private so can only be altered by public methods.
Every class must also have a constructor method, which is called ‘new’. A constructor
allows a new object to be created.

Question 32

Immediate Addressing

Answer 32

The operand is the actual value upon which the instruction is to be
performed, represented in binary

Question 33

Direct Addressing

Answer 33

The operand gives the address which holds the value upon which the
instruction is to be performed. Direct addressing is used in LMC.

Question 34

Indirect Addressing

Answer 34

The operand gives the address of a register which holds another address,
where the data is located.

Question 35

Indexed Addressing

Answer 35

An index register is used, which stores a certain value. The address of the
operand is determined by adding the operand to the index register. This is
necessary to add an offset in order to access data stored contiguously in
memory such as in arrays

Question 36

ADD

Answer 36

Add the value at the given memory address to the
value in the Accumulator

Question 37

SUB

Answer 37

Subtract the value at the given memory address
from the value in the Accumulator

Question 38

STA

Answer 38

Store the value in the Accumulator at the given
memory address

Question 39

LDA

Answer 39

Load the value at the given memory address into the
Accumulator

Question 40

INP

Answer 40

Allows the user to input a value which will be held in
the Accumulator

Question 41

OUT

Answer 41

Prints the value currently held in the Accumulator

Question 42

HLT

Answer 42

Stops the program at that line, preventing the rest of
the code from executing.

Question 43

DAT

Answer 43

Creates a flag with a label at which data is stored.

Question 44

BRZ

Answer 44

Branches to a given address if the value in the Accumulator is zero. This is a conditional branch.

Question 45

BRP

Answer 45

Branches to a given address if the value in the Accumulator is positive. This is a conditional branch.

Question 46

BRA

Answer 46

Branches to a given address no matter the value in the Accumulator. This is an unconditional branch.