PCAP-31-03 4.1 Understand the Object-Oriented Approach PCAP-31 Practice Questions (Page 5)

Questions 21–25

1. 21expert · easy

   A developer is reviewing a class definition and needs to identify which attributes are instance attributes and which are class attributes. Given the following code: class Employee: company = "ACME" def __init__(self, name): self.name = name Which statement is correct?

   • Acompany is a class attribute, name is an instance attribute.
   • BBoth are instance attributes.
   • CBoth are class attributes.
   • Dcompany is an instance attribute, name is a class attribute.
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2. 22expert · medium

   A developer is designing a class for a bank account. The class has a private attribute __balance and a method get_balance() that returns the balance. The developer wants to allow external code to add money to the account, but only through a method that validates the amount is positive. Which method should be added?

   • Adef add(self, amount): self.__balance += amount
   • Bdef set_balance(self, amount): self.__balance = amount
   • Cdef deposit(self, amount): self.__balance += amount
   • Ddef deposit(self, amount): if amount > 0: self.__balance += amount
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4. 23expert · medium

   A developer is creating a class to represent a point in 2D space. The class should have x and y coordinates and a method distance_from_origin() that returns the Euclidean distance. Which class definition correctly implements this?

   • Aclass Point: def __init__(self, x, y): self.x = x self.y = y def distance_from_origin(self): return self.x + self.y
   • Bclass Point: def __init__(self, x, y): self.x = x self.y = y
   • Cclass Point: def distance_from_origin(self): return 0
   • Dclass Point: def __init__(self, x, y): self.x = x self.y = y def distance_from_origin(self): return (self.x**2 + self.y**2) ** 0.5
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5. 24expert · medium

   A developer is working with a class that has a private attribute __secret. They want to provide read-only access to it from outside the class. Which approach is best?

   • AUse a class attribute to store the secret.
   • BMake the attribute public by renaming it to secret.
   • CUse a global variable for the secret.
   • DProvide a method get_secret() that returns self.__secret.
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6. 25application · medium

   A banking app stores account balances. The developer wants to prevent accidental direct modification of the balance attribute from outside the class. Which approach should be used?

   • AUse a global variable for the balance.
   • BName the attribute balance and rely on developers to not modify it.
   • CName the attribute __balance and provide a method deposit() that updates it.
   • DUse a class attribute instead of an instance attribute.
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