**Course Title:** Mastering C#: From Fundamentals to Advanced Programming **Section Title:** Object-Oriented Programming in C# **Topic:** Introduction to classes, objects, and methods. **Overview** In this topic, we will delve into the fundamental concepts of object-oriented programming (OOP) in C#: classes, objects, and methods. You will learn how to define and use classes, create objects, and implement methods to interact with your objects. By the end of this topic, you will understand the basics of object-oriented programming in C# and be able to create your own classes, objects, and methods. ### Classes in C# In C#, a class is a blueprint or a template that defines the properties and behaviors of an object. A class is essentially a design pattern or a template that defines the characteristics of an object. When you create a class, you define its properties (data) and methods (functions). To define a class in C#, you use the `class` keyword followed by the name of the class. For example: ```csharp public class Car { // Properties public string Make { get; set; } public string Model { get; set; } public int Year { get; set; } // Method public void DisplayCarInfo() { Console.WriteLine($"Make: {Make}, Model: {Model}, Year: {Year}"); } } ``` In this example, the `Car` class has three properties: `Make`, `Model`, and `Year`. It also has a method called `DisplayCarInfo()` that displays the car's information. ### Objects in C# An object is an instance of a class. You can create multiple objects from the same class, and each object will have its own set of properties and behaviors. To create an object from a class, you use the `new` keyword followed by the name of the class and the parentheses `()`. For example: ```csharp Car myCar = new Car(); ``` You can then access the object's properties and methods using the dot notation. For example: ```csharp myCar.Make = "Toyota"; myCar.Model = "Corolla"; myCar.Year = 2022; myCar.DisplayCarInfo(); ``` ### Constructors in C# A constructor is a special method in a class that is called when an object is created. A constructor is used to initialize the object's properties and set up any necessary resources. To define a constructor in C#, you use the same name as the class, and it does not have a return type. For example: ```csharp public class Car { public string Make { get; set; } public string Model { get; set; } public int Year { get; set; } public Car(string make, string model, int year) { Make = make; Model = model; Year = year; } public void DisplayCarInfo() { Console.WriteLine($"Make: {Make}, Model: {Model}, Year: {Year}"); } } ``` In this example, the `Car` class has a constructor that takes three parameters: `make`, `model`, and `year`. The constructor initializes the object's properties using the `make`, `model`, and `year` parameters. ### Methods in C# Methods are functions that belong to a class or an object. Methods can perform various actions on an object or return a value. To define a method in C#, you use the `public` access modifier followed by the return type and the method name. For example: ```csharp public class Car { public string Make { get; set; } public string Model { get; set; } public int Year { get; set; } public void DisplayCarInfo() { Console.WriteLine($"Make: {Make}, Model: {Model}, Year: {Year}"); } public int GetAge() { return 2024 - Year; } } ``` In this example, the `Car` class has two methods: `DisplayCarInfo()` and `GetAge()`. The `DisplayCarInfo()` method displays the car's information, and the `GetAge()` method returns the car's age. **Best Practices** * Use meaningful names for your classes, objects, and methods. * Keep your methods short and concise. * Use access modifiers to control the visibility of your methods and properties. * Use constructors to initialize your objects. * Use methods to perform actions on your objects. **Additional Resources** * [MSDN: Classes and Objects](https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/) * [MSDN: Constructors](https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/constructors) * [MSDN: Methods](https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/methods) **Leave a Comment or Ask for Help** If you have any questions or need help with any of the concepts covered in this topic, please leave a comment below. In the next topic, we will cover understanding encapsulation, inheritance, and polymorphism.