IB Computer Science HL · Year 2 · Lesson 14
Single-class OOP applied design/programming
Object-oriented programming models a problem through classes and objects, with clear responsibilities and controlled access to state.
Paper 250 minutesB3.1.1 · B3.1.2 · B3.1.3 · B3.1.4 · B3.1.5
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Today’s targets
What you need to be able to do
2 / 7
- EvaluateThe fundamentals of OOP
- ConstructA design of classes, their methods and behaviour
- DistinguishBetween static and non-static variables and methods
- ConstructCode to define classes and instantiate objects
B3.1.1B3.1.2B3.1.3B3.1.4B3.1.5
Paper 2 lensMatch the depth of every response to the command term. Previously learned content can move quickly, but retrieval must still be accurate.
Page 2 of 7
Retrieve
Rapid Recall Deck
3 / 7
Say the answer aloud before flipping. Mark secure knowledge quickly and spend time on the gaps.
- What information should a well-designed single class group together?: State that belongs to the entity and methods that operate on or expose that state.
- How does a constructor support object correctness?: It ensures an object begins life with the required initial state instead of relying on later setup.
- How do instance and static members differ in ownership?: Instance members belong to each object; static members belong to the class and are shared.
- How does encapsulation improve a single-class design?: It keeps internal state controlled and exposes only the operations other code should use.
- What should a UML class design show before coding?: The class name, relevant attributes, methods, and any required visibility or relationships.
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Consolidate
Rebuild the topic from memory
4 / 7
Closed-notes retrievalReconstruct the core ideas, operations, diagrams and trade-offs before checking earlier lessons.
- B3.1.1 The fundamentals of OOP
- B3.1.2 A design of classes, their methods and behaviour
- B3.1.3 Between static and non-static variables and methods
- B3.1.4 Code to define classes and instantiate objects
- B3.1.5 And apply the concepts of encapsulation and information hiding in OOP
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Apply
Transfer to a new scenario
5 / 7
ScenarioA library-management application needs a design or technical decision related to today’s topic. Explain what matters and why.
- Model real-world entities using OOP concepts: classes, objects, inheritance, encapsulation, polymorphism
- The advantages and disadvantages of using OOP in various programming scenarios
- Classes and their methods, based on application requirements
- Use of unified modelling language (UML) class diagrams to represent class relationships, attributes and methods, to aid effective software design and planning
- Compare static and non-static variables and methods, including their usage and scope
- When to use instance variables instead of class variables, and how to apply these concepts effectively in code
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Exam lens
Paper 2 practice
6 / 7
Build the response before checking notesUse precise terminology and match the required depth.
- Evaluate: The fundamentals of OOP in the context of a library-management application.
- Construct: A design of classes, their methods and behaviour in the context of a library-management application.
- Distinguish: Between static and non-static variables and methods in the context of a library-management application.
Self-checkAnswer the exact command term. For explain, include mechanism/reason; for compare, pair criteria; for discuss/evaluate/justify, build supported reasoning and a conclusion.
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Homework
Finish the learning cycle
7 / 7
IA — main task
Continue Criterion D development. Keep code readable, record meaningful implementation decisions, and maintain testing/evidence notes as you work.
Syllabus — short
Complete one targeted Paper 2/Paper 1 retrieval task from today’s lesson.
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End of Lesson 14.