2.2

Question 1

2.2.1
1. What is modularity?
2. What are the different names for modules?

Answer 1

1. Modularity is breaking a large program or problem down into smaller chunks, where each module carries out a single, specific task.
2. The different names for modules are: subroutines, procedures, functions and methods.

Question 2

2.2.1
1. What is a procedure?
2. What is a function?

Answer 2

1. A procedure is a block of code that takes in zero, one or more parameters and performs a set task, but does not return a value.
2. A function is a block of code that takes in zero, one or more parameters, performs a set task, and returns a value. The return value from a function does not need to be assigned to a variable, as long as it returns a valid item.

Question 3

2.2.1
1. What is the outline of a subroutine?
2. What are the two methods for passing data into a subroutine?

Answer 3

1. The first line of a subroutine specifies the interface for that subroutine. The basic outline is: the name of the subroutine, the list of parameters it requires when it is called, the order of those parameters, and the data type for those parameters, and if it is a function, then it also includes a return value.
2. The two methods for passing data into a subroutine are: passing by value, passing by reference.
   Passing by value means the variable used is a local variable self-contained within the function. Passing by reference means editing the global variable in the program.

Question 4

2.2.2
1. What is systems development lifestyle (SDLC)?
2. What is iterative development?

Answer 4

1. A framework defining tasks performed to each step in the software development process.
2. Iterative development is a process, or a method, in which a software product is developed after breaking it down into smaller, easily developable ‘chunks’. Each chunk is analysed, designed, developed and tested in repeated cycles (iterations).

Question 5

2.2.2
1. What is a prototype?
2. What is risk analysis?
3. What is a methodology?

Answer 5

1. An original or first model of something from which other forms are copied or developed. Early prototypes will likely have reduced functionality.
2. The process of identifying and analysing potential issues that could negatively impact a software project. Risk factors in software development include inadequate estimation of time, cost, scope and resources.
3. A methodology is a system of methods and principles for doing something.

Question 6

2.2.2
1. What is the waterfall methodology?
2. What are the advantages of waterfall (list 4)?
3. What are the disadvantages of waterfall (list 5)?

Answer 6

1. The model is sequential/linear. The next phase can only start when the previous phase has finished. The stages are: developing the requirements, design, coding, testing, and operations.
2. Lots of strong documentation.
   Sequential design process, so client knows what to expect, such as time frame and cost, as the project is planned in advance.
   It suits large projects, which are more likely to have stable requirements.
3. You are unable to easily go back to previous stages.
   The product is only tested once competed, so if there are bugs early on, a large amount of code will be effected.
   It does not leave room for changing project requirements.
   There is no customer involvement, so end product might not meet users needs.

Question 7

2.2.2
1. What is agile?
2. What are the four values of agile?

Answer 7

1. Agile development is an umbrella term for methods and practices based on the values and principles expressed in the Agile Manifesto.
2. 1) Individuals and interactions over processes and tools.
   2) Working software over comprehensive documentation.
   3) Customer collaboration over contract negotiation.
   4) Responding to change over following a plan.

Question 8

2.2.2
What are the twelve principles of agile?

Answer 8

Satisfy the customer (1) and welcome changing requirements. (1)
Close, daily cooperation between business people and developers (1) - face to face communication is best. (1)
Working software is delivered frequently (1) and used measure progress. (1)
Continuous attention to technical excellence and good design. (1)
Sustainable development (1) and simplicity. (1)
Self organising teams (1), that are trusted and motivated (1), and reflect on how to become more effective, then adjusts their behavior. (1)

Question 9

2.2.2
What is extreme programming?

Answer 9

Extreme programming is a software development methodology, which is an agile paradigm. The focus is on good quality code, and is designed to allow development to respond to changing user requirements. The program is divided into planned iterations, where specific tasks are developed, and the program is regularly reviewed.

Question 10

2.2.2
1. What are the three advantages of XP?
2. What are three disadvantages of XP?

Answer 10

1. Quality of code should be very high.
   Continuous testing results in fewer issues further down in the development process,
   It allows development to respond to changing user requirements.
   The project is divided into planned iterations where frequent small releases are developed.
2. Programmers need to be based in the same geographic location for pair programming.
   Customer needs to provide a representative to work with the development team.
   Little or no documentation.

Question 11

1. What is the outline of a subroutine?
2. What are the two methods for passing data into a subroutine?

Answer 11

1. The first line of a subroutine specifies the interface for that subroutine. Depending on the programming language, the layout of a subroutine is slightly different, but the basic outline is: the name of the subroutine, the list of parameters it requires when it is called, the order of those parameters, and the data type for those parameters, and if it is a function, then it also includes a return value.
2. The two methods for passing data into a subroutine are: passing by value, passing by reference.
   Passing by value means the variable used is a local variable self-contained within the function. Passing by reference means editing the global variable in the program.

Question 12

1. What is RAD?
2. What are the stages of RAD?

Answer 12

1. Rapid Application Development (RAD): A software development methodology that produces a prototype with reduced functionality to a set deadline. Good for small, short projects with changing requirements.
2. A prototype with reduced functionality is created to a set deadline. It is then tested and feedback obtained from clients is used to inform the next prototype. If needed, changes are made and a further prototype is evaluated by the customer. This process repeats until the final prototype becomes the final product. Each iteration is usually time boxed (produced within a limited time).

Question 13

1. What are the merits of RAD?
2. What are the drawbacks of RAD?
3. When might RAD be used?

Answer 13

1. Program can accommodate changing requirements as the development is iterative
   Reduced development time due to minimising planning
   Time boxing can help keep projects on track
2. Good code is not prioritised
   Demanding on customer’s time for feedback
3. RAD projects are typically small scale and of short duration, and when the customer is unsure of their requirements. RAD should be used only when a system can be modularized to be delivered in an incremental manner.

Question 14

1. What is the spiral model?
2. What are the stages of the spiral model?

Answer 14

1. A software development methodology that is iterative, focuses on risk, and prototypes are developed during each cycle.
2. There are 4 phases: determine objective, identify and resolve risks, development and testing, and planning the next iteration. The cycle keeps repeating until the product is operational, and it can then be released

Question 15

1. What are the advantages of the spiral model?
2. What are the disadvantages of the spiral model?
3. When can the spiral model be used?

Answer 15

1. Ideal for risky and complex projects; there is a focus on eliminating unattractive risky alternatives early on. If risks are too high, the project may be stopped before prototyping
   Changing requirements can be accommodated
   Users see the system early - likely to result in a solution which better matches user’s needs
   Focus on alternatives encourages software reuse
2. Management and process is more complex so could be more expensive
   Good risk analysts are expensive
   Efficient code is not prioritized
   No continuous customer interaction
3. It is effective when the risks are high. It should also be used if significant changes are expected in the product during the development cycle, and is effective if the customer is not sure of their requirements.It should be used only when a system can be modularized to be delivered in an incremental manner.