PCPP-32-101 1.3 Understand and Use Inheritance, Polymorphism, and Composition PCPP-32-1 Practice Questions (Page 5)

Questions 21–25

1. 21application · medium

   A developer is writing a function that saves data to a storage backend. The function should work with any object that has a save(data) method, including Database, FileStorage, and CloudStorage classes. The developer wants to avoid modifying the function when new storage backends are added. Which approach is best?

   • AUse a dictionary to map backend names to save functions.
   • BCall save() directly on the object without type checking.
   • CUse isinstance() to check for each known backend and call save() accordingly.
   • DCreate an abstract base class Storage and require all backends to inherit from it.
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2. 22application · medium

   A developer is writing a function that processes payment methods. The function should accept any object that has a `pay(amount)` method, regardless of its class. The system currently has CreditCard and PayPal classes, both with a `pay` method. Which approach best implements this requirement?

   • AUse isinstance() checks to verify the object is either CreditCard or PayPal before calling pay().
   • BSimply call the pay() method on the object and rely on duck typing.
   • CCreate an abstract base class Payment and require all payment classes to inherit from it.
   • DUse a try-except block to catch AttributeError if pay() does not exist.
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4. 23foundation · easy

   Which code snippet correctly implements multiple inheritance?

   • Aclass Child(Parent1): class Parent2: pass
   • Bclass Child(Parent1, Parent2): pass
   • Cclass Child: pass Child.inherit(Parent1, Parent2)
   • Dclass Child(Parent1): pass class Child(Parent2): pass
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5. 24expert · hard

   A developer has a class hierarchy: class A: def greet(self): return 'A'; class B(A): def greet(self): return 'B'; class C(A): def greet(self): return 'C'; class D(B, C): pass. An instance of D calls greet(). What is the result?

   • AAn AttributeError is raised
   • B'A'
   • C'C'
   • D'B'
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6. 25foundation · easy

   What is the key difference between single and multiple inheritance in Python?

   • ASingle inheritance allows a class to inherit from one parent, while multiple inheritance allows a class to inherit from more than one parent.
   • BSingle inheritance prevents method overriding, while multiple inheritance allows it.
   • CSingle inheritance requires a common base class, while multiple inheritance does not.
   • DSingle inheritance is only for built-in types, while multiple inheritance is for user-defined classes.
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