IB Computer Science: Object-Oriented Programming Revision

Object-Oriented Programming is a core part of IB Computer Science. Revise the key concepts and common mistakes below, then lock them in with the free games.

Key concepts

Class and objectClass is template; object is instance with state and behaviour; Simula 1967 introduced OOP concepts.

EncapsulationBundling data and methods; restricting direct access via private fields and public getters/setters.

InheritanceSubclass inherits attributes and methods from superclass; allows code reuse and is-a relationships.

PolymorphismOne interface, many implementations; method overriding and overloading; runtime dispatch.

Abstract classCannot be instantiated; declares interface and may include partial implementation; concrete subclasses required.

UML class diagramBoxes show class name, attributes, methods; arrows show inheritance and association (OMG standard 1997).

InterfaceContract of method signatures to implement.

Concrete classProvides full implementation; instantiable.

UMLUnified Modeling Language for software diagrams.

Class diagramShows classes, attributes, methods, relations.

AssociationLink between classes - composition, aggregation.

Design patternReusable template for design problems.

SingletonEnsures one instance globally.

ObserverSubjects notify subscribers on change.

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