Object-Oriented Programming (OOP) : MCQs & PYQs with Explanation

Option C

Inheritance is a fundamental concept in object-oriented programming (OOP) where one class acquires the properties (data fields) and methods of another class. The class inheriting the properties is called the derived class or subclass or child class, while the class from which it inherits is called the base class or superclass or parent class. Inheritance promotes code reusability.

Option C

Encapsulation in Java is one of the fundamental principles of Object-Oriented Programming (OOP). An act of combining data (variables) and the methods that operate on that data into a single unit called a class. 
Through encapsulation, the internal details of an object are hidden from the outside world, allowing controlled access via getter and setter methods. This helps maintain data security, ensures better control over the data, and prevents unintended modification.

Option B

In object-oriented programming, a class is a blueprint for creating objects and can encapsulate (combine) data (variable) and operations (methods). The degree of primitiveness of a class refers to how basic or elementary its responsibilities are.

• A primitive class is a very basic class that performs simple, specific operations only.
• It does not try to do everything or handle complex logic. Instead, it focuses on fundamental building blocks that can be used by other, more complex classes.
• A class that does only primitive operations is said to have a high degree of primitiveness.

Option B

Object-Oriented Programming (OOP) is based on several important features that help in designing reusable, secure, and manageable programs. The major features of OOP are:

• Encapsulation.
• Inheritance.
• Data Abstraction.
• Polymorphism.

Option C

In Object-Oriented Programming (OOP), objects communicate and interact with each other by sending messages. A message usually means calling methods or functions of another object.

• An object contains data (attributes), and functions (methods).
• When one object wants another object to perform some action, it sends a message by invoking its method.

#include<iostream>
using namespace std;
class Result
{
public:
    void showMarks()
    {
        cout<<"Marks=77";
    }
};
class Student
{
public:
    void requestResult(Result r)
    {
        r.showMarks();   // Message sent to Result object
    }
};
int main()
{
    Result r1;
    Student s1;
    s1.requestResult(r1);
    return 0;
}