OOPS in Python

1. Which of the following best describes encapsulation?

• Hiding implementation details and exposing only necessary parts through a public interface
• Dividing a program into multiple functions
• Using loops to repeat code
• Writing code in multiple files for modularity

Answer explanation

Encapsulation hides internal state and provides controlled access via methods.

2. What will be printed by the following code?

• 5
• 10
• None
• Error

Answer explanation

B calls A.__init__ (value=5) then adds 5, so display prints 10.

3. In OOP, 'is-a' relationship is implemented through:

• Aggregation
• Composition
• Inheritance
• Encapsulation

Answer explanation

Inheritance models the 'is-a' relationship between classes.

4. What is the output?

• 5 1
• 5 0
• Error
• 1 5

Answer explanation

Default parameter n=1; x1 has 5, x2 has 1; __str__ returns those.

5. Which is TRUE about method overriding?

• Child method same name, different number of parameters
• Child method must have same name and parameters as parent
• Overridden methods must return None
• Overriding works only for static methods

Answer explanation

Overriding requires same signature to redefine parent behavior.

6. What will the following code output?

• Base
• Derived
• Error
• None

Answer explanation

Derived.__init__ replaces Base.__init__; data is set to 'Derived'.

7. Which of these is NOT an advantage of OOP?

• Code reuse through inheritance
• Better organization through encapsulation
• Reduced execution time for all programs
• Polymorphism enabling flexibility

Answer explanation

OOP improves design and reuse; it does not guarantee faster runtime.

8. What will this print?

• True True
• True False
• False True
• False False

Answer explanation

p has attribute 'greet' and it is a callable method.

9. Which concept allows objects of different classes to be treated as objects of a common superclass?

• Aggregation
• Polymorphism
• Inheritance
• Encapsulation

Answer explanation

Polymorphism enables a common interface for multiple underlying forms.

10. What will this code print?

• 1 1 1
• 2 2 2
• 1 1 2
• Error

Answer explanation

Class variable 'count' is shared; incremented twice ‚Üí 2 for both instances and class.