Define these Object-Oriented Programming (OOP) terms: Instance Inheritance Polymorphism

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2022). The mark or mark type is shown in brackets.

1. [3] One mark for each correct OOP term definition:
2. • Instance – an occurrence of an object // a specific object based on the class // an instantiation of a class.
3. • Inheritance - the capability of defining a new class of objects that has all the attributes and methods from a parent class.
4. • Polymorphism – allows the same method to take on different behaviours depending on which class is instantiated // methods can be redefined for derived classes.
5. [5] One mark for each point:
6. • Car and ENDCLASS
7. • Four declarations – must use the identifiers used in the assignments
8. • Constructor header – must use CarBodyType
9. • Two assignments – must use CarMake
10. • Constructor identifier for the car model and the identifier in the Model assignment statement match
11. CLASS Car PRIVATE Make : STRING PRIVATE Model : STRING PRIVATE BodyType : STRING PRIVATE Fuel : STRING PRIVATE NumberBuilt : INTEGER PUBLIC PROCEDURE NEW (CarMake : STRING, CarModel : STRING, CarBodyType : STRING) Make ← CarMake Model ← CarModel BodyType ← CarBodyType Fuel ← "" NumberBuilt ← 0 ENDPROCEDURE getFuel() getNumberBuilt() ENDCLASS