考纲要点

Syllabus 20.1.2 — Inheritance

#	Point	Exam Frequency
1	Define inheritance: deriving a new class from an existing class	★☆☆
2	Understand parent class (base/superclass) and child class (derived/subclass)	★★★
3	Write class Child(Parent): to declare inheritance	★★★
4	Call super().__init__(params) in child constructor to initialise inherited attributes	★★★
5	Override methods: redefine method with exact same name and parameters in child	★★★
6	Use super().method_name() to call parent method from child	★★★
7	Understand that child inherits all non-private attributes and methods from parent	★★☆
8	Child class can add new attributes and new methods not in parent	★★★
9	Create objects of both parent and child classes in main program	★★★
10	Demonstrate polymorphism: calling same method on parent and child objects gives different behaviour	★★☆

Inheritance Hierarchy Keywords

• Inheritance — class Child(Parent):
• Constructor chaining — super().__init__(...)
• Method overriding — redefine in child
• Code reuse — child reuses parent's code via super()
• Polymorphism — same method name, different implementations

What You Must Be Able To Do

1. Read a parent class definition and write a child class that:

   • Calls parent constructor
   • Adds new private attributes
   • Overrides at least one method

2. Write a main program that:

   • Creates instances of both parent and child
   • Calls methods on both
   • Outputs results

3. Read data from a text file and create appropriate parent / child objects based on record type

4. Trace through inheritance code and predict output (paper 1 style)