Book Image

Hands-On Object-Oriented Programming with C#

By : Raihan Taher
Book Image

Hands-On Object-Oriented Programming with C#

By: Raihan Taher

Overview of this book

Object-oriented programming (OOP) is a programming paradigm organized around objects rather than actions, and data rather than logic. With the latest release of C#, you can look forward to new additions that improve object-oriented programming. This book will get you up to speed with OOP in C# in an engaging and interactive way. The book starts off by introducing you to C# language essentials and explaining OOP concepts through simple programs. You will then go on to learn how to use classes, interfacesm and properties to write pure OOP code in your applications. You will broaden your understanding of OOP further as you delve into some of the advanced features of the language, such as using events, delegates, and generics. Next, you will learn the secrets of writing good code by following design patterns and design principles. You'll also understand problem statements with their solutions and learn how to work with databases with the help of ADO.NET. Further on, you'll discover a chapter dedicated to the Git version control system. As you approach the conclusion, you'll be able to work through OOP-specific interview questions and understand how to tackle them. By the end of this book, you will have a good understanding of OOP with C# and be able to take your skills to the next level.
Table of Contents (16 chapters)

The sealed class

One of the principles of OOP is inheritance, but sometimes you may need to restrict inheritance in your code for the sake of your application's architecture. C# provides a keyword called sealed. If this keyword is placed before a class's signature, the class is considered a sealed class. If a class is sealed, that particular class can't be inherited by other classes. If any class tries to inherit a sealed class, the compiler will throw an error. Structs can also be sealed, and in that case, no class can inherit that struct.

Let's look at an example of a sealed class:

sealed class Animal {
public string name;
public int ageInMonths;
public void Move(){
Console.WriteLine("Moving");
}
public void Eat(){
Console.WriteLine("Eating");
}
}
public static void Main(){
Animal dog = new Animal();
...