PCPP-32-101 1.7 Understand Attribute Encapsulation PCPP-32-1 Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A `Document` class has a `_content` attribute. The developer needs to provide a way to read the content, replace it with new content (after checking that the new content is not empty), and clear it entirely. Which set of methods should be implemented?

   • Aget_content() and set_content(value) only
   • Bget_content() and del_content() only
   • Cget_content(), set_content(value), and del_content()
   • Dset_content(value) and del_content() only
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2. 2expert · hard

   A developer is maintaining a `Person` class with a `_age` attribute. The class is used in multiple parts of the codebase, and some legacy code directly accesses `person._age`. The developer wants to add validation (age must be between 0 and 150) without breaking the legacy code. What is the best approach?

   • AConvert `_age` to a property with getter and setter, and keep the attribute name `_age`.
   • BCreate a new class `ValidatedPerson` and migrate all code to use it.
   • CRename `_age` to `__age` and update all legacy code to use the new name.
   • DAdd validation in the `__init__` method only.
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4. 3application · medium

   A developer is explaining encapsulation to a junior colleague. The colleague asks why the `_balance` attribute in a `BankAccount` class should not be accessed directly as `account._balance`. What is the most accurate reason?

   • ADirect access is slower than using the getter method.
   • BDirect access bypasses the methods that enforce business rules like overdraft limits.
   • CDirect access is not allowed because the attribute is private by language design.
   • DDirect access will cause a syntax error in Python.
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5. 4expert · hard

   A developer is designing a `BankAccount` class with a `_balance` attribute. The requirements are: (1) balance can be read at any time, (2) deposits must add a positive amount, (3) withdrawals must not make the balance negative, and (4) the account can be closed, which resets the balance to zero. The developer wants to use a single setter method for both deposits and withdrawals. What is the best design?

   • AImplement `get_balance()` and `update_balance(delta)` where `delta` can be positive or negative.
   • BImplement `get_balance()`, `deposit(amount)`, `withdraw(amount)`, and `close_account()` methods.
   • CImplement `get_balance()`, `set_balance(value)`, and `del_balance()` where `set_balance` validates that the value is non-negative.
   • DImplement `get_balance()` and `set_balance(value)` where `set_balance` accepts a new balance directly.
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6. 5application · medium

   A library management system has a `Book` class with a `_available` boolean attribute. The developer wants to ensure that the availability status can only be changed through a method that also updates the last-modified timestamp. What does this design primarily achieve?

   • AIt makes the code more readable by hiding the timestamp logic.
   • BIt prevents the availability from being read by other classes.
   • CIt keeps the availability status and the timestamp consistent.
   • DIt allows the Book class to be subclassed more easily.
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