Module 3 - Chapter 1: Fundamentals of Object-Oriented Programming (OOP) in C#
Object-Oriented Programming (OOP) is a paradigm that uses "objects" to design applications and computer programs. It utilizes several principles such as encapsulation, inheritance, and polymorphism to create more modular, reusable, and flexible code. C#, being a modern object-oriented language, fully supports these concepts, making it a powerful tool for developing complex software systems. This chapter introduces the fundamentals of OOP in C#, covering classes and objects, properties and methods, constructors and destructors, and the concept of static members.
Fundamentals of Object-Oriented Programming (OOP) in C#
Object-Oriented Programming (OOP) is a paradigm that uses "objects" to design applications and computer programs. It utilizes several principles such as encapsulation, inheritance, and polymorphism to create more modular, reusable, and flexible code. C#, being a modern object-oriented language, fully supports these concepts, making it a powerful tool for developing complex software systems. This chapter introduces the fundamentals of OOP in C#, covering classes and objects, properties and methods, constructors and destructors, and the concept of static members.
Classes and Objects
At the heart of OOP are classes and objects. A class is a blueprint for creating objects (a particular data structure), providing initial values for state (member variables or attributes), and implementations of behavior (member functions or methods). An object is an instance of a class.
Defining a Class
public class Dog
{
// Fields, properties, methods, and events go here...
public string Name;
public void Bark()
{
Console.WriteLine("Woof!");
}
}
Creating an Object
Dog myDog = new Dog();
myDog.Name = "Buddy";
myDog.Bark(); // Outputs: Woof!
Properties and Methods
Properties are special methods called accessors. This allows you to access class data safely. Methods define the behaviors or functionalities of your object.
Property Example
public class Person
{
private string name; // field
// Property
public string Name
{
get { return name; }
set { name = value; }
}
}
Method Example
public class Calculator
{
public int Add(int a, int b)
{
return a + b;
}
}
Constructors and Destructors
A constructor is a special method of the class that is automatically called when an instance of a class is created. A destructor is used to destroy instances of a class.
Constructor Example
public class Book
{
public Book() // Constructor
{
Console.WriteLine("A new book object has been created!");
}
}
Destructor Example
public class Demo
{
~Demo() // Destructor
{
// Cleanup statements...
Console.WriteLine("Destructor is called when object is destroyed.");
}
}
Static Members
Static members belong to the class itself instead of an instance of the class. This means that they can be called without an object.
Static Method Example
public class Utility
{
public static void SayHello()
{
Console.WriteLine("Hello!");
}
}
Call a static method:
Utility.SayHello();
Summary
Understanding the fundamentals of OOP in C# is essential for building robust and scalable software. By leveraging classes and objects, encapsulating data with properties, defining behavior with methods, initializing objects with constructors, and utilizing static members, you can develop well-structured and efficient applications. This foundation will also prepare you for more advanced OOP concepts such as inheritance, polymorphism, and interfaces.
In C#, delegates and events are foundational concepts that enable a flexible and extensible way to handle method callbacks and notifications. They play a crucial role in designing and implementing event-driven programming patterns, which are central to developing interactive applications such as graphical user interfaces, game development, and service-oriented applications. This chapter introduces delegates and events, explaining their uses, syntax, and how they enable managed event handling in C#.
Encapsulation is a fundamental concept in object-oriented programming (OOP) that involves bundling the data (attributes) and methods (functions) that operate on the data into a single unit, known as a class. It also restricts direct access to some of the object's components, which is a way of preventing accidental manipulation of data and ensuring internal data integrity. This principle of hiding the internal state and requiring all interaction to occur through an object's methods is central to C#. This chapter explains the concept of encapsulation and demonstrates how to implement it in C# through access modifiers and properties.
Functions are a cornerstone of programming, allowing developers to encapsulate code that performs a specific task into a reusable and maintainable block. In C#, functions are defined within classes or structs, and they are referred to as methods. This chapter will dive into the basics of defining and using functions in C#, covering their syntax, types, parameters, and return values. Understanding functions is crucial for both beginners and intermediate developers, as they provide the building blocks for structuring and organizing code in any application.
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