Object-Oriented Programming (OOP)

Q1. What is the 'new' keyword used for?

1. A.Deleting an existing object from memory
2. B.Declaring a new variable in the scope
3. C.Defining a new method in the class
4. D.Creating a new instance of a class✓ Correct

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Q2. What is a class in OOP?

1. A.A variable type for storing data
2. B.A blueprint for creating objects✓ Correct
3. C.A loop construct for iteration
4. D.A reusable function for operations

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Q3. What is encapsulation?

1. A.Inheriting properties from a parent class definition
2. B.A sorting method that orders elements in a collection
3. C.A type of iterative loop control structure in code
4. D.Bundling data and methods while restricting direct access✓ Correct

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Q4. What is a constructor?

1. A.A static method belonging to the class itself
2. B.A getter method that returns a field value
3. C.A destructor that cleans up object state
4. D.A special method called when creating an object✓ Correct

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Q5. What is an object in OOP?

1. A.A standalone function
2. B.A class definition in code
3. C.A primitive data type
4. D.An instance of a class✓ Correct

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Q6. What is inheritance in OOP?

1. A.Acquiring properties and methods from a parent class✓ Correct
2. B.Creating a new object instance from a class
3. C.A form of encapsulation that hides internal details
4. D.A design pattern for structuring application code

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Q7. What does the 'this' keyword refer to?

1. A.The current object instance✓ Correct
2. B.A static method reference
3. C.The class definition itself
4. D.The parent class reference

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Q8. What is an access modifier?

1. A.A keyword controlling member visibility level✓ Correct
2. B.A data type for storing numeric values only
3. C.A type of loop construct in the language
4. D.A constructor for initializing object state

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Q9. What is a method in OOP?

1. A.A standalone function not tied to any class
2. B.A function defined inside a class for objects✓ Correct
3. C.A variable that stores data in the program
4. D.A data type that defines value constraints

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Q10. What is an interface?

1. A.A class with full method implementations provided
2. B.A contract defining method signatures without bodies✓ Correct
3. C.An abstract class with some methods implemented
4. D.A type of variable for storing object references

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Q11. What is polymorphism?

1. A.A class relationship defined by inheritance hierarchy
2. B.A type of encapsulation hiding internal data details
3. C.Different objects responding differently to same method✓ Correct
4. D.Having only one single form of behavior always

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Q12. What is the difference between method overloading and method overriding?

1. A.They are the same concept with different names in different languages
2. B.Overloading requires an inheritance hierarchy between the classes involved
3. C.Overriding changes the method parameter list in the parent class definition
4. D.Overloading: same name different params; overriding: same signature in subclass✓ Correct

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Q13. What is a static method?

1. A.A method belonging to the class not any specific instance✓ Correct
2. B.A constructor method for initializing new object state
3. C.A method that can never be overridden by subclasses
4. D.A private method accessible only within the same class

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Q14. What is the super keyword?

1. A.A global variable accessible everywhere in code
2. B.A reference to parent class for calling its members✓ Correct
3. C.The main class that serves as program entry point
4. D.A type of access modifier restricting member access

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Q15. What is the difference between composition and inheritance?

1. A.Composition is always slower than inheritance in performance
2. B.Inheritance is an is-a relationship; composition is has-a✓ Correct
3. C.They are exactly the same concept with no difference at all
4. D.Inheritance is more flexible and loosely coupled overall

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Q16. What are getter and setter methods?

1. A.Static methods belonging to the class directly
2. B.Methods for controlled field read and write access✓ Correct
3. C.Loop constructs for iterating over collections
4. D.Constructor types for initializing objects

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Q17. What is an abstract class?

1. A.A fully implemented class with all methods defined
2. B.A static class that only contains class-level members
3. C.A final class that cannot be extended by other classes
4. D.A class that cannot be instantiated with abstract methods✓ Correct

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Q18. What is the SOLID principle in OOP?

1. A.A coding style guide for naming conventions in code
2. B.A data structure for organizing elements efficiently
3. C.Five design principles: SRP, OCP, LSP, ISP, and DIP✓ Correct
4. D.A testing framework for validating software behavior

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Q19. What is a mixin?

1. A.A class that mixes different data types together randomly
2. B.A class providing methods to others without being standalone✓ Correct
3. C.A type of interface that defines a strict method contract
4. D.A structural design pattern for building complex objects

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Q20. What is the object slicing problem in C++?

1. A.Splitting an object into smaller component parts for storage
2. B.When assigning derived to base variable, derived data is lost✓ Correct
3. C.A memory allocation issue caused by fragmented heap storage
4. D.A threading problem from concurrent access to shared objects

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Q21. What is the Liskov Substitution Principle (LSP)?

1. A.A design pattern for constructing complex object hierarchies
2. B.A principle for sorting elements in a collection efficiently
3. C.A rule for managing memory allocation in large applications
4. D.Subclass objects should be substitutable for superclass objects✓ Correct

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Q22. What is a virtual method table (vtable)?

1. A.A hash table for caching method results quickly
2. B.A debug table for tracking method execution and logging
3. C.A lookup table for resolving dynamic method calls at runtime✓ Correct
4. D.A method list defined in the source code of the program

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Q23. What is the fragile base class problem?

1. A.A compilation error from missing method implementations
2. B.A memory leak caused by improper object disposal code
3. C.A class that is too small to be useful on its own
4. D.Base class changes can break derived classes unexpectedly✓ Correct

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Q24. What is the diamond problem?

1. A.An error related to geometric shapes in rendering code
2. B.A memory leak issue caused by circular object references only
3. C.An ambiguity when inheriting from classes with common ancestor✓ Correct
4. D.A compilation warning about unused variables in the program

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Q25. What is the difference between prototype-based and class-based OOP?

1. A.Prototype-based OOP is always slower than class-based OOP overall
2. B.Class-based uses blueprints; prototype-based clones existing objects✓ Correct
3. C.They are the same approach with no meaningful differences at all
4. D.Class-based OOP cannot support any form of inheritance at all

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Q26. What is multiple inheritance and which languages support it?

1. A.Creating multiple instances of the same class simultaneously
2. B.Inheriting from a single parent class in a linear hierarchy
3. C.Inheriting from multiple parents; supported by C++ and Python✓ Correct
4. D.All programming languages support this feature universally

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Q27. What is the difference between association, aggregation, and composition?

1. A.Association is general; aggregation weak; composition strong ownership✓ Correct
2. B.They are all identical concepts with just different names used
3. C.Composition is always the better design choice in every single case
4. D.Only naming differences exist with no behavioral distinctions at all

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Q28. What is covariant return type?

1. A.A generic type parameter used in collection class definitions
2. B.Allowing an overriding method to return a more specific subtype✓ Correct
3. C.Always returning the exact same type as the parent declares
4. D.A type error that occurs when return types do not match up

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Q29. What is double dispatch and how does it differ from single dispatch?

1. A.Single dispatch uses two methods while double dispatch uses only one
2. B.There is no practical difference between the two dispatch mechanisms
3. C.Single dispatch selects by one type; double dispatch by two types✓ Correct
4. D.Double dispatch is twice as fast in execution as single dispatch

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Q30. What is metaclass programming?

1. A.Creating graphical user interfaces programmatically
2. B.Writing classes whose instances are themselves classes✓ Correct
3. C.A commonly used structural design pattern for code
4. D.Programming about programs in general terms

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