Let's create a simple library management system using the concepts we've covered throughout this series. The system will manage books, users, and borrow records. The project will include classes, inheritance, interfaces, events, delegates, generics, collections, LINQ, and exception handling. using System; using System.Collections.Generic; using System.Linq; // Chapter 2.1: Understanding classes, objects, and inheritance public class User { // Chapter 2.4: Understanding properties and indexers public int Id { get ; set ; } public string Name { get ; set ; } public DateTime JoinDate { get ; set ; } // Chapter 2.2: Understanding constructors and destructors public User( int id, string name) { Id = id; Name = name; JoinDate = DateTime.Now; } // Chapter 2.3: Understanding access modifiers (public, private, protected, internal) protected void PrintUserDetails() { Console.WriteLine( $ "ID: {I...

 Introduction: In the previous article , Chapter 6.3, we discussed the System.Collections and System.Collections.Generic namespaces, which provide classes for working with collections of objects in C# applications. In this final article of our series, we'll explore the System.Linq namespace, which offers powerful querying capabilities for collections, allowing you to filter, sort, and transform data with ease. After completing this article, you should have a solid understanding of C# and its core concepts. We encourage you to start a project to implement what you've learned and further strengthen your skills. System.Linq Namespace: The System.Linq namespace provides Language Integrated Query (LINQ) functionality, which allows you to perform complex queries on collections using a concise and expressive syntax. LINQ works with both generic and non-generic collections, as well as with other data sources like XML and relational databases. Some key features of LINQ include: ...

 Introduction: In the previous article , Chapter 6.2, we explored the System.Text and System.Text.Encoding namespaces, which are important for working with text and character encodings in C# applications. In this article, we'll discuss the System.Collections and System.Collections.Generic namespaces, which provide classes for working with collections of objects. In the next article, we'll dive into the System.Linq namespace, which offers powerful querying capabilities for collections. System.Collections Namespace: The System.Collections namespace provides non-generic collection classes, such as ArrayList, Hashtable, and Queue. These classes store objects, but they don't enforce type safety: ArrayList list = new ArrayList(); list.Add(42); list.Add( "Hello, world!" ); foreach ( object item in list) { // Process item } System.Collections.Generic Namespace: The System.Collections.Generic namespace offers type-safe, generic collection classe...

 Introduction: In the previous article , Chapter 6.1, we discussed the System.IO namespace, which provides classes for working with files, directories, and streams. In this article, we'll explore the System.Text and System.Text.Encoding namespaces, which are important for working with text and character encodings in C# applications. In the next article, we'll discuss the System.Collections and System.Collections.Generic namespaces, which are essential for working with collections of objects. System.Text Namespace: The System.Text namespace contains classes and interfaces for working with text and character encodings. Some key classes include: StringBuilder: Provides a mutable string buffer for efficient string manipulation. Encoding: Represents a character encoding, such as UTF-8, UTF-16, or UTF-32. Decoder/Encoder: Convert between different character encodings and byte arrays. StringBuilder: The StringBuilder class is useful for efficient string manipula...

 Introduction: In this new chapter, we'll explore working with .NET classes, which are essential for developing robust and efficient C# applications. In this first article, we'll discuss the System.IO namespace, which provides classes for working with files, directories, and streams. In the next article, we'll delve into the System.Text and System.Text.Encoding namespaces, which are important for working with text and character encodings. System.IO Namespace: The System.IO namespace contains classes for performing various operations on files, directories, and streams. Some key classes include: File: Provides static methods for creating, copying, deleting, and moving files, as well as opening files for reading and writing. Directory: Provides static methods for creating, deleting, and moving directories, and enumerating files and directories. FileStream: Represents a file stream, allowing you to read and write data to a file. StreamReader/StreamWriter:...

 Introduction: In the previous article , Chapter 5.1, we discussed reading and writing text and binary files, essential skills for working with data in C#. In this article, we'll explore serialization and deserialization of objects, which are important for persisting and restoring object states. In the next article, we'll discuss working with .NET classes, an important aspect of developing C# applications. Serialization: Serialization is the process of converting an object's state into a format that can be stored or transmitted. In C#, the .NET framework provides several serialization mechanisms, such as binary, XML, and JSON serialization: // Binary Serialization BinaryFormatter formatter = new BinaryFormatter(); using (FileStream stream = new FileStream( "data.bin" , FileMode.Create)) { formatter.Serialize(stream, myObject); } Deserialization: Deserialization is the process of reconstructing an object's state from a serialized forma...

 Introduction: In this new chapter, we'll explore File I/O and Serialization, essential concepts for working with data in C#. In this first article, we'll discuss reading and writing text and binary files. In the next article, we'll delve into serialization and deserialization of objects, which are important for persisting and restoring object states. Reading and Writing Text Files: C# provides several classes for reading and writing text files, such as StreamReader, StreamWriter, and File: // Writing a text file using (StreamWriter writer = new StreamWriter( "example.txt" )) { writer.WriteLine( "Hello, world!" ); } // Reading a text file using (StreamReader reader = new StreamReader( "example.txt" )) { string line; while ((line = reader.ReadLine()) != null ) { Console.WriteLine(line); } } Reading and Writing Binary Files: For working with binary files, C# provides the BinaryReader and Bina...

 Introduction: In the previous article , Chapter 4.2, we explored heap and stack memory, which are crucial for understanding how memory is allocated and managed in a C# program. In this article, we'll delve into garbage collection and finalization, essential concepts for managing memory resources efficiently in a C# application. In the next article, we'll discuss file I/O and serialization, another important aspect of working with data in C#. Garbage Collection: Garbage collection is the process of automatically reclaiming memory that is no longer in use. The garbage collector (GC) is responsible for managing heap memory, identifying objects that are no longer accessible, and deallocating their memory. This helps prevent memory leaks and ensures that your application uses memory efficiently: Person person = new Person( "John" , "Doe" ); // Memory allocated on the heap person = null ; // Now eligible for garbage collection Generations: Th...

 Introduction: In the previous article , Chapter 4.1, we discussed the differences between reference and value types. In this article, we'll explore heap and stack memory, which are crucial for understanding how memory is allocated and managed in a C# program. This topic is of great importance, so we'll cover it in detail. In the next article, we'll discuss garbage collection and finalization, which are essential for managing memory resources efficiently in a C# application. Heap Memory: Heap memory is a region of memory where objects are dynamically allocated during the runtime of a program. When you create an instance of a reference type, memory is allocated on the heap. Heap memory is managed by the garbage collector, which automatically reclaims memory that is no longer in use: Person person = new Person( "John" , "Doe" ); // Memory allocated on the heap Stack Memory: Stack memory is a region of memory where value types and method...

 Introduction: In this new chapter, we'll focus on memory management and garbage collection, which are essential for understanding how resources are managed in a C# application. In this first article, we'll explore the differences between reference and value types. In the next article, we'll discuss heap and stack memory, which are crucial for understanding how memory is allocated and managed in a C# program. Reference Types: Reference types store a reference to the memory location where the data is stored. When you create an instance of a reference type, the memory is allocated on the heap. Classes, interfaces, delegates, and arrays are examples of reference types: Person person1 = new Person( "John" , "Doe" ); Person person2 = person1; person2.FirstName = "Jane" ; Console.WriteLine(person1.FirstName); // Output: Jane Value Types: Value types store the actual data, and when you create an instance of a value type, the memo...

 Introduction: Welcome to the next chapter of our C# learning series! In this chapter, we'll dive into advanced C# concepts to further enhance your understanding of the language. In this article, we'll discuss LINQ and lambda expressions, two powerful features that simplify data manipulation and make your code more expressive. In the next article, we'll explore exceptions and debugging, essential techniques for building robust and reliable applications. LINQ (Language Integrated Query): LINQ is a set of features in C# that allows you to perform complex data queries directly in the language, without having to use SQL or another query language. LINQ can be used with various data sources, such as arrays, collections, XML, and databases. It provides a consistent query syntax, making it easier to work with different types of data: int [] numbers = { 2, 5, 1, 6, 8, 3, 7 }; var evenNumbers = from number in numbers where number % 2 == 0 ...

 Introduction: In the previous article , Chapter 3.3, we discussed generics and anonymous types, important concepts for creating flexible and reusable code. In this article, we'll explore reflection and dynamic programming, powerful techniques for working with types and objects at runtime. In the next topic, we'll dive into memory management and garbage collection, which are essential for understanding how resources are managed in a C# application. Reflection: Reflection is a feature in C# that allows you to inspect and interact with the metadata of types, objects, and assemblies at runtime. You can use reflection to create instances of types, invoke methods, get and set property values, and more: Type personType = typeof (Person); MethodInfo methodInfo = personType.GetMethod( "SayHello" ); object [] parameters = new object [] { "John" }; string result = ( string )methodInfo.Invoke( null , parameters); Console.WriteLine(result); Dynamic...

 Introduction: In the previous article , Chapter 3.2, we discussed exceptions and debugging, essential techniques for building robust and reliable applications. In this article, we'll explore generics and anonymous types, which are important concepts for creating flexible and reusable code. In the next chapter, we'll dive into reflection and dynamic programming, powerful techniques for working with types and objects at runtime. Generics: Generics allow you to create classes, methods, and interfaces that can work with different types without sacrificing type safety. By using generics, you can create reusable and type-safe code without the need for casting or boxing: public class GenericList <T> { private T[] data; private int count; public GenericList( int size) { data = new T[size]; count = 0; } public void Add(T item) { data[count++] = item; } public T Get( int index) { retur...

 Introduction: In our previous article , Chapter 3.1, we explored LINQ and lambda expressions, which are powerful tools for simplifying data manipulation and making your code more expressive. In this article, we'll discuss exceptions and debugging, essential techniques for building robust and reliable applications. In the next chapter, we'll dive into generics and anonymous types, which are important concepts for creating flexible and reusable code. Exceptions: Exceptions are events that occur during the execution of a program when an error or an exceptional condition occurs. They can be caught and handled using try-catch-finally blocks. The try block contains the code that may throw an exception, the catch block contains the code to handle the exception, and the finally block contains code that will always be executed, regardless of whether an exception was thrown or not: try { int result = 10 / 0; } catch (DivideByZeroException ex) { Console.WriteLine( ...

 Introduction: We have covered various aspects of Object-Oriented Programming with C# in our previous articles . In this article, we'll explore properties, indexers, and operator overloading, which are powerful tools for creating expressive and user-friendly classes in C#. In the next chapter, we'll move on to advanced C# concepts. Properties: Properties are a way to provide access to an object's data while encapsulating the underlying storage mechanism. They can be used to define validation rules or perform other actions when getting or setting a value. Properties are declared using the get and set accessors: class Person { private string name; public string Name { get { return name; } set { name = value .Trim(); } } } You can also use auto-implemented properties with default get and set accessors: class Person { public string Name { get ; set ; } } Indexers: Indexers allow objects to be indexe...

 Introduction: In our previous articles , we discussed various aspects of Object-Oriented Programming with C#, such as classes, objects, inheritance, constructors, destructors, interfaces, delegates, and events. In this article, we'll explore access modifiers, which control the visibility and accessibility of class members. In the next article, we'll cover properties, indexers, and operator overloading. Public: The public access modifier allows class members to be accessible from any code in the same assembly or another assembly that references it. This is the least restrictive access level: public class Person { public string Name { get ; set ; } public int Age { get ; set ; } } Private: The private access modifier restricts the visibility of class members to the containing class. This is the most restrictive access level and is the default access level for class members: class Person { private string name; private int age; ...

 Introduction: In the previous articles , we covered various aspects of Object-Oriented Programming with C#, including classes, objects, inheritance, interfaces, delegates, and events. In this article, we'll discuss constructors and destructors, which are essential components of object lifecycle management in C#. In the next article, we'll explore access modifiers, such as public, private, protected, and internal. Constructors: A constructor is a special method in a class that gets called when an object is created. Constructors are used to initialize the object's state, set default values for fields, and perform any setup required. To define a constructor, use the class name as the method name and no return type: class Person { public string Name { get ; set ; } public int Age { get ; set ; } public Person( string name, int age) { Name = name; Age = age; } } // Usage Person person = new Person( "John" , 30...

 Introduction: In our previous article , we explored classes, objects, and inheritance in the context of Object-Oriented Programming with C#. In this article, we'll delve into interfaces, delegates, and events, which are crucial concepts for designing flexible, modular, and maintainable applications in C#. In the next article, we'll cover constructors and destructors. Interfaces: An interface is a contract that defines a set of methods and properties a class must implement. Interfaces promote loose coupling and ensure that classes adhere to a specific structure. To define an interface, use the interface keyword followed by the interface name: interface IPrintable { void Print(); } To implement an interface in a class, use the : symbol followed by the interface name: class Document : IPrintable { public void Print() { Console.WriteLine( "Printing the document..." ); } } Delegates: A delegate is a type-safe fun...

 Introduction: In the previous articles , we covered the fundamentals of C#, including data types, variables, operators, control structures, and arrays and collections. Now, we will dive into the world of Object-Oriented Programming (OOP) with C#. In this article, we'll explore the concepts of classes, objects, and inheritance. In the next post, we will discuss interfaces, delegates, and events. Classes and Objects: A class is a blueprint for creating objects, which are instances of the class. A class can contain fields, properties, methods, and events that define the state and behavior of objects created from the class. To define a class, use the class keyword followed by the name of the class: class Person { // Fields, properties, methods, and events go here } To create an object (an instance of a class), use the new keyword followed by the class name and parentheses: Person person1 = new Person(); Inheritance: Inheritance is a fundamental...

Introduction: FAANG companies (Facebook, Amazon, Apple, Netflix, and Google) are renowned for their rigorous software engineering interviews, with system design questions playing a crucial role. These questions assess your ability to design large-scale, scalable, and maintainable systems. In this blog post, we present 10 real-life system design questions that you may encounter during FAANG interviews, along with the type of system architecture each question represents and a brief description of aspects to consider while designing the system. Design a system like Twitter (Social Media Platform) In this question, you will be asked to design a social media platform that can handle massive amounts of data and scale to accommodate millions or billions of users. Focus on aspects like data modeling, data storage, feed generation, and search functionality. This will demonstrate your understanding of distributed systems, databases, and caching strategies. Design a URL shortening service like bi...