Object-Oriented Programming Basics

Questions and Answers

What does an object represent in object-oriented programming?

A collection of classes

A real-world entity with properties and behavior (correct)

A set of functions only

A type of access modifier

What is a class in object-oriented programming?

A collection of functions only

A blueprint or template for creating objects (correct)

An instance of an object

A data hiding mechanism

Which of the following correctly describes access specifiers?

They are used only in data functions.

They serve as attributes of an object.

They define the class name.

They control how members of a class can be accessed. (correct)

Which keyword is used to define a class in C++?

class Signup and view all the answers

What analogy is used to explain the relationship between a class and an object?

A recipe and the meal made from it Signup and view all the answers

Which of the following is NOT an access specifier in C++?

Global Signup and view all the answers

When an object is created from a class, what does it inherit?

All variables and functions from the class Signup and view all the answers

What are members of a class comprised of?

Data members and member functions Signup and view all the answers

Study Notes

Objects

An object is a real-world entity characterized by Reference/Identity, Behavior, & Property.
Objects serve as the fundamental unit in object-oriented programming, encapsulating both data and functions.
An object is an instance of a class, similar to how a cake is an instance of a recipe.
Each object created from a class inherits attributes and behaviors defined in the class.

Classes

A class is a collection or template of objects, acting as a blueprint that defines properties and behaviors.
Classes establish the structure, behavior, and attributes that an object will have.
To create a class, the class keyword is used, following a specific syntax.

Class Syntax

The basic syntax for defining a class is:

class class_name {
    // Access specifier;
    // Data member;
    // Member function / Methods;
};

Access Specifiers

Access specifiers control the visibility and accessibility of class members, enforcing data hiding.
There are three primary types of access specifiers in C++:
- Public: Members are accessible from anywhere in the program.
- Private: Members are only accessible within the class itself.
- Protected: Members are accessible within the class and its subclasses.

Access Specifier Syntax

The syntax for defining access specifiers in a class:

class ClassName {
    private:
        // Declare private members/methods here.
    public:
        // Declare public members/methods here.
    protected:
        // Declare protected members/methods here.
};

Example Class

An example of a simple class in C++:

class MyClass {
    public:
        int publicVar;    // Accessible from anywhere
    private:
        int privateVar;   // Accessible only from within the class
    protected:
        int protectedVar; // Accessible from class and its subclasses

    public:
        // Constructor definition
        MyClass() { 
            publicVar = 1; 
            privateVar = 2; 
            protectedVar = 3; 
        }

        // Method to display values
        void displayValues() { 
            cout << "Public: " << publicVar << " Private: " << privateVar << " Protected: " << protectedVar; 
        }
};

The constructor initializes the properties of the object when an instance is created.

Description

This quiz covers the fundamental concepts of object-oriented programming, including objects, classes, and access specifiers. Understanding these principles is essential for creating organized and efficient code in any object-oriented language. Test your knowledge on how classes and objects interact and the syntax used to define them.