Chapter 12 - Software Development

Question 1

What is the purpose of a development life cycle?

Answer 1

• it is a structured process used to design, build, and test software solutions, where each stage of the cycle has a specific purpose
• choice of program development cycle depends on the method required to produce the program
• it ensures that programs are developed systematically, efficiently, and to a high standard
• helps developers to solve real-world problems

Question 2

Describe the stages of the development life cycle in general.

Answer 2

1. analysis: understanding the problem the product is being created to solve and gathering user requirements and needs
2. design: planning how the product will work
3. coding: translating the design into a usable product by writing code in modules using a suitable programming language (which one is best suited to control the production line)
4. testing: thoroughly testing the code with a variety of test data to ensure it meets the original requirements, handles a variety of input correctly, and performs reliably under different conditions
5. maintenance: ensures the program remains reliable over time

Question 3

Describe how the analysis stage uses abstraction.

Answer 3

• used to ignore unnecessary information, makes the solution easier to design
  1. core functionality
  2. constraints (limits the product works within)

Question 4

How are requirement documents used in the analysis stage?

Answer 4

• breaks down the problem into manageable parts
• labels each requirement
• describes what success looks like for each feature

Question 5

What tools are used to create blueprints for the solution during the design stage?

Answer 5

• structure diagrams: breaks down the program into smaller components
• flowcharts: shows the logical flow of processes
• pseudocode: outlines how the logic will be written in code

Question 6

How are code modules tested during the coding stage?

Answer 6

• iterative testing is used, meaning that each module is tested and debugged individually as it’s created
• they are retested whenever changes are made, to ensure no new errors are present

Question 7

What does the maintenance stage involve?

Answer 7

• fixing bugs that were not present during testing
• updating features to meet new requirements
• improving performance or adapting to new systems

Question 8

What is the waterfall model?

Answer 8

• a sequential software development process divided into distinct phases
• each phase must be completed before the next phase begins

Question 9

What situation is the waterfall model most suited for?

Answer 9

• projects where requirements are well understood and likely to change
• projects where high quality and compliance is required, with a clear goal of the project’s goals and constraints

Question 10

Describe the steps of the waterfall model.

Answer 10

1. requirement gathering and analysis: all possible system requirements to be developed are recorded clearly
2. system design: the requirements are translated into a design, with the overall architecture and main components identified
3. implementation: actual code written based on the designs
4. integration and testing: all components and modules are integrated and tested to ensure the whole system works as expected
5. deployment: software handed over to the market/client
6. maintenance: regular maintenance done post-release for fixing bugs, improving performance or adding features

Question 11

Describe the advantages of the waterfall model.

Answer 11

• simple and linear
• clear stages and milestones
• ideal for well-defined projects

Question 12

Describe the disadvantages of the waterfall model.

Answer 12

• inflexible, difficult to make changes once development begins
• expensive to fix late problems
• long development cycle: no working software until late in the life cycle so slower to market than competitors
• needs high involvement of the client

Question 13

What is the iterative (agile) model?

Answer 13

• a type of agile software development methodology that promotes adaptability and high customer involvement

Question 14

What situation is the iterative model most suited for?

Answer 14

• small to medium sized projects where requirements can change
• high customer involvement

Question 15

Describe the steps of the iterative model.

Answer 15

1. identify user requirements: gather functional and non-functional requirements (usually stories) from stakeholders
2. sprint planning: select a set of tasks broken down from the requirements to complete during the current sprint (short time-boxed period); outline the sprint goal
3. design solution: decide how the tasks will be built, focusing on simplicity and adaptability
4. develop features: write code, in pairs/groups
5. test continuously: ongoing unit, integration, and accepting testing
6. sprint review: demo to stakeholders for feedback
7. sprint retrospective: team post-mortem, focusing on team performance and process optimisation
8. release: deploy working software to users/staging environment after every sprint/set of sprints
9. repeat: continue to next sprint with new knowledge and feedback

Question 16

Describe the benefits of the iterative model.

Answer 16

• highly adaptable; responds quickly to changing requirements
• promotes constant collaboration
• encourages good design and continuous testing
• ensures products meet real needs

Question 17

Describe the disadvantages of the iterative model.

Answer 17

• requires experienced team members
• risk of burnout
• may lock documentation
• scope creep: changing goals may lead to uncontrolled growth

Question 18

What is the Rapid Application Development (RAD) model?

Answer 18

• form of agile software development methodology that emphasises fast and iterative development

Question 19

What situation is the RAD model most suited for?

Answer 19

• projects where rapid delivery is needed
• projects where requirements can be developed and refined as the project progresses

Question 20

Describe the steps of the RAD model.

Answer 20

1. the general system requirements, constraints and assumptions are gathered
2. develop prototypes, ensuring they match user requirements
3. build the system incrementally with rapid construction, feedback, and adaptation
4. deploy the product into a live environment
5. provide maintenance based on user feedback and needs

Question 21

Describe the advantages of the RAD model.

Answer 21

• rapid development and delivery at a relatively low cost
• high user involvement shaping the system throughout
• adaptable to changing requirements
• incremental development

Question 22

Describe the disadvantages of the RAD model.

Answer 22

• requires skilled and cohesive teams
• potential quality issues such as documentation issues due to speed
• too complex for small projects
• scope creep risk

Question 23

What is scope creep?

Answer 23

• uncontrolled or unapproved expansion of a project’s requirements, goals, or deliverables after the project has already begun
• occurs in small, seemingly insignificant increments
• doesn’t consider the projects time, budget, and resources

Question 24

what are structure charts and their purpose?

Answer 24

• a modelling tool used in the design stage of program development that decomposes a problem into smaller sub-problems, representing each as a module
• it focuses on what the program will do, not how it does it

Question 25

what are state-transition diagrams and their purpose?

Answer 25

- they show how a system moves between different states based on inputs

Question 26

what are the common types of error

Answer 26

- syntax: error that breaks the grammatical rules of a programming language and stops it from running - logic: incorrect code is used that causes the program to run, but produces an incorrect output - runtime: error that causes a program to crash

Question 27

what are some examples of runtime errors

Answer 27

- dividing by 0 - calling an index out of array bounds - stack overflow - unable to read or write a drive

Question 28

what are some examples of logic errors

Answer 28

- incorrect use of operators - logical operator confusion - indexing arrays incorrectly - infinite loops

Question 29

what are some examples of syntax errors

Answer 29

- typos and spelling errors - missing/extra brackets or quotes - misplaced or missing semicolons - invalid variable or function names

Question 30

what is testing?

Answer 30

- process of checking for logic errors, unexpected behaviour, and operational integrity during the testing stage of the program development life cycle once the program has been written and compiled - a detailed test plan should be made that outlines the test cases and expected results during the analysis stage

Question 31

describe the common methods of testing

Answer 31

- dry run: manually trace through the code to predict output and track variables - walkthrough: step by step review of the code with others to identify issues early on - white-box: tests the internal logic and code structure, the tester knows how the program works - black-box: tests the inputs and expected outputs without knowing the internal workings - integration: checks that different components work correctly together - alpha: performed in-house by the developers during early testing - beta: performed by external users in real-world environments - acceptance: final check to ensure the program meets the original client requirements - stub: uses temporary components called stubs to stimulate missing components during early testing

Question 32

describe the types of test data

Answer 32

- normal: data that should be accepted as an input - abnormal: wrong data type - extreme: maximum and minimum values of normal data that are accepted - boundary: tests data on either side of the maximum and minimum values

Question 33

what is program maintenance?

Answer 33

- process of updating or improving a program after it has been delivered to the user - it is needed to fix errors that were missed during testing; to improve performance based on user feedback; to adapt the software to new uses or platforms

Question 34

describe the types of program maintenance

Answer 34

- corrective: fixes bugs or errors found during real-world use - adaptive: modifies the program to support new environments or requirements - perfective: improves performance or adds small enhancements