12.1 Program Development Life Cycle

Stages of Development Life Cycle

• Analysis

  • Firstly the problem must be identified and detailed requirements or specification may be documented
  • The inputs, process, output and UI needs to be recognized
  • Uses tools like abstraction and decomposition in this stage
  • Abstraction:
    • Filtering out unnecessary details and only working with the relevant data
    • Reduces the complexity of algorithm
  • Decomposition of the problem
    • Breaking down a problem into simpler and smaller subproblems which is easier to handle
    • Every computer system is made up of subsystems, which are made up of further sub-systems
    • Program Modules (Procedure/Function): Reusable block of code designed to perform a specific task
    • Algorithms are decomposed into these parts: Inputs, Processes, Outputs, Storage
  • Stepwise Refinement: Process of breaking down a complex problem or system into smaller, more manageable components in a step-by-step manner to simplify design and implementation.

• Design

  • Program specification from the analysis stage is used to design the logic plan and algorithms
  • Documentation: Written text or instructions explaining how a system or software works, helping users or developers understand and use it effectively
    • Documentation uses methods like Structure Charts, Flowchart, Pseudocode, Structured english
    • Structured English: A subset of English that consist of command statements used to describe an algorithm

• Coding

  • The main program is written down or developed based on the design
  • Different modules may use different language and maybe created by different teams
  • Testing is done to make sure the modules work as expected
  • Iterative Testing: Conducting tests on modules, making changes as required and repeating these until all requirements are met

• Testing and Debugging

  • The completed program is now tested using different type of test data or inputs to identify the errors
  • The bugs or issues identified in the application is corrected

• Deployment and Maintenance

  • Revise internal documentation and create user end documentation
  • Publish the application or deploy it to the relevant site (May be to client or in app store)
  • Provide customer care and support as required
  • Provide training, education or tutorials for the users
  • Correct any bugs and make modifications as users require

Types of Development Life Cycles

• Waterfall

  • Fundamental model of software development
  • Linear model where each phase is completed before moving to the next
  • Advantage: Easier to manage, Suitable for projects with well-defined requirements and minimal expected changes
  • Disadvantage: Inflexible, Late testing lead to delayed discovery of issues

• Iterative

  • Project is developed in small, repeated cycles
  • Project at first is small and it becomes complex overtime
  • Advantage: Errors identified and fixed early, More adaptable
  • Disadvantage: Requires more resource due to repeated cycle, Project may become sidetracked from main plan

• Rapid Application Development (RAD)

  • Fast paced method that focuses on building the prototype
  • Makes changes on that prototype using iterative feedbacks
  • Advantage: Suitable for tight timeline and flexible requirements
  • Disadvantage: Results in lower quality documentation, Might not be scalable in long run, Relies on user feedback and skilled team which is not always available