PCPP-32-101 1.3 Understand and Use Inheritance, Polymorphism, and Composition PCPP-32-1 Practice Questions (Page 2)

Questions 6–10

1. 6foundation · easy

   What is the core idea behind duck typing in Python?

   • AAn object must be an instance of a class that implements a specific interface.
   • BAn object must inherit from a specific base class to be used in polymorphic code.
   • CAn object's type is checked explicitly before any method is called.
   • DAn object's suitability is determined by the presence of required methods and attributes, not by its type.
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2. 7application · medium

   A developer is building a reporting system where Report, Invoice, and Summary all share common formatting logic. The developer wants to reuse the formatting code but also allow each class to customize the header. Which approach is most appropriate?

   • ACreate a base class Formatter with a format() method, and have Report, Invoice, and Summary inherit from it, overriding format() where needed.
   • BCreate a Formatter class and pass it as an attribute to Report, Invoice, and Summary instances.
   • CDuplicate the formatting logic in each class to avoid inheritance complexity.
   • DUse a standalone function that takes a type parameter to switch between formatting behaviors.
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4. 8application · medium

   A developer is building a logging system. The system has FileLogger and ConsoleLogger classes, both with a log(message) method. A LoggerManager class needs to use either logger based on configuration. Which design is most appropriate?

   • ADuplicate the log() logic in LoggerManager.
   • BHave LoggerManager accept a logger object in its constructor and call its log() method.
   • CMake LoggerManager inherit from both FileLogger and ConsoleLogger.
   • DCreate a single Logger class with a type attribute to switch behavior.
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5. 9application · medium

   A developer is writing a function that calculates the area of any shape. The function should work with Circle, Rectangle, and Triangle classes, each having an area() method. The developer wants to ensure the function can handle future shape classes without modification. Which approach is best?

   • AUse a dictionary to map shape names to area functions.
   • BCall area() directly on the object without type checking.
   • CUse isinstance() to check for each shape type and call area() accordingly.
   • DCreate an abstract base class Shape and require all shapes to inherit from it.
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6. 10application · medium

   A developer is modeling a system for a vehicle rental company. Each Vehicle has an Engine, and each Car is a Vehicle. The company also needs to model a Truck that is a Vehicle but has a CargoBed. The developer wants to avoid code duplication and ensure that changes to the Engine class automatically affect all vehicles. Which design best satisfies these requirements?

   • ADefine a Vehicle class that contains all engine and cargo functionality, and have Car and Truck inherit from it.
   • BDefine separate Car and Truck classes that each contain their own engine logic, with no shared Vehicle base class.
   • CDefine Engine, Car, and Truck classes that all inherit from a common Vehicle class, with Engine as a subclass of Vehicle.
   • DDefine an Engine class, a Vehicle class that contains an Engine instance, and Car and Truck classes that inherit from Vehicle.
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