OOPs Interview Questions and Answers

Ques 16. Explain the concept of multiple inheritance.

Multiple inheritance allows a class to inherit properties and behaviors from more than one superclass. Some languages support it directly, while others provide alternatives like interfaces.

Ques 17. What is a friend class in C++?

In C++, a friend class is a class that is not a part of the class hierarchy but is granted access to the private and protected members of another class.

Ques 18. What is the SOLID principle in OOP?

SOLID is an acronym for five design principles in OOP: Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion. These principles aim to make software designs more understandable, flexible, and maintainable.

Ques 19. What is a virtual function?

A virtual function is a function in a base class that is declared using the 'virtual' keyword and can be overridden by a derived class. It enables dynamic method binding and polymorphism.

Example:

class Shape {
  virtual calculateArea() = 0;
}

Ques 20. What is an abstract method?

An abstract method is a method declared in an abstract class or an interface that has no implementation in the base class. Subclasses must provide an implementation for abstract methods.

Example:

abstract class Printer {
  abstract print();
}