PCPP-32-101 1.3 Understand and Use Inheritance, Polymorphism, and Composition PCPP-32-1 Practice Questions (Page 3)

Questions 11–15

1. 11foundation · easy

   How should an is-a relationship be modeled in Python?

   • ABy using a function that takes both classes as arguments.
   • BBy using a decorator to link the two classes.
   • CBy using composition, where the child class contains an instance of the parent class.
   • DBy using inheritance, where the child class inherits from the parent class.
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2. 12expert · hard

   A developer has the following classes: class A: def method(self): return 'A'; class B(A): def method(self): return 'B'; class C(A): def method(self): return 'C'; class D(B, C): def method(self): return super().method() + 'D'. What does D().method() return?

   • A'CD'
   • B'BD'
   • C'BCD'
   • D'AD'
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4. 13application · medium

   A developer is modeling a university system. A Department has many Professors, and each Professor has a Department. The developer wants to ensure that when a Department is deleted, its Professors are also deleted, but the Department can exist without Professors. Which design best models this?

   • ADepartment contains a list of Professor instances; Professor contains a reference to Department.
   • BProfessor inherits from Department.
   • CDepartment and Professor are standalone classes with no relationship.
   • DDepartment inherits from Professor.
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5. 14application · medium

   A developer is writing a function that plays audio. The function should work with any object that has a `play()` method, including MP3Player, StreamingService, and Radio classes. The developer wants to avoid modifying the function when new audio sources are added. Which approach is best?

   • ADefine an abstract base class AudioSource and have all classes inherit from it.
   • BUse isinstance() to check for each known class and call play() accordingly.
   • CUse a dictionary to map class names to play functions.
   • DCall play() directly on the object without checking its type.
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6. 15application · medium

   A developer is building a shape hierarchy. The base class Shape has an area() method. Circle and Rectangle inherit from Shape and override area(). The developer wants to add a Square class that is a Rectangle with equal sides. Which class hierarchy is most appropriate?

   • ARectangle inherits from Square.
   • BSquare inherits from Rectangle and overrides the constructor to set equal sides.
   • CSquare contains a Rectangle instance as an attribute.
   • DSquare and Rectangle are both standalone classes with no inheritance.
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