Introduction to C#

If you're coming from Java, you'll find C# remarkably familiar. In fact, C# was designed with Java developers in mind, and the two languages share many conceptual similarities while each taking their own approach to modern software development.

What is C#?

C# (pronounced "C-sharp") is a modern, object-oriented programming language developed by Microsoft and first released in 2000 as part of the .NET initiative. The language was primarily designed by Anders Hejlsberg, who previously worked on Turbo Pascal and Delphi at Borland before joining Microsoft.

Why Was C# Created?

Microsoft developed C# as a key component of their .NET framework for several reasons:

• Platform control: To have a flagship language fully optimized for the Windows ecosystem and Microsoft's development platforms
• Modern language features: To incorporate lessons learned from Java, C++, and other languages while adding innovative features
• Enterprise development: To provide a robust, type-safe language for building large-scale business applications
• Rapid evolution: Unlike Java at the time, Microsoft wanted a language they could evolve quickly to meet developer needs

Primary Uses of C#

C# has become one of the most versatile programming languages, used for:

• Desktop applications: Windows applications using WPF or WinForms
• Web development: ASP.NET and ASP.NET Core for server-side web applications
• Game development: Unity game engine uses C# as its primary scripting language
• Mobile apps: Xamarin and .NET MAUI for cross-platform mobile development
• Cloud services: Azure cloud applications and microservices
• APIs: RESTful services and web APIs

Key Similarities with Java

Both languages share fundamental concepts:

• Object-oriented programming with classes and interfaces
• Garbage collection for automatic memory management
• Strong static typing
• Similar syntax for basic constructs (loops, conditionals, etc.)
• Exception handling with try-catch blocks
• Generics for type-safe collections

Key Differences from Java

While similar, C# offers several distinctions:

1. Properties

C# has first-class support for properties, eliminating the need for verbose getter/setter methods.

Java:

public class Person {
    private String name;
    
    public String getName() {
        return name;
    }
    
    public void setName(String name) {
        this.name = name;
    }
}

C#:

public class Person {
    public string Name { get; set; }
}

2. LINQ (Language Integrated Query)

C# features LINQ, a powerful query syntax built directly into the language:

List<int> numbers = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

// Filter and transform in one elegant expression
var evenSquares = numbers
    .Where(n => n % 2 == 0)
    .Select(n => n * n)
    .ToList();

// Result: [4, 16, 36, 64, 100]

3. Delegates and Events

C# has built-in delegate types and an event system:

public class Button {
    public event EventHandler Clicked;
    
    public void Click() {
        Clicked?.Invoke(this, EventArgs.Empty);
    }
}

// Usage
button.Clicked += (sender, e) => Console.WriteLine("Button clicked!");

4. Structs

C# supports value types through structs, unlike Java where everything (except primitives) is a reference type:

public struct Point {
    public int X { get; set; }
    public int Y { get; set; }
    
    public Point(int x, int y) {
        X = x;
        Y = y;
    }
}

5. Async/Await

C# has native, elegant asynchronous programming support:

Java (using CompletableFuture):

CompletableFuture.supplyAsync(() -> fetchData())
    .thenApply(data -> processData(data))
    .thenAccept(result -> System.out.println(result));

C#:

public async Task ProcessDataAsync() {
    var data = await FetchDataAsync();
    var result = ProcessData(data);
    Console.WriteLine(result);
}

6. Extension Methods

Add methods to existing types without inheritance:

public static class StringExtensions {
    public static bool IsPalindrome(this string str) {
        return str.SequenceEqual(str.Reverse());
    }
}

// Usage
bool result = "racecar".IsPalindrome(); // true

Basic Code Example: Complete Program

Here's a simple console application comparing Java and C#:

Java:

import java.util.ArrayList;
import java.util.List;

public class Program {
    public static void main(String[] args) {
        List<String> names = new ArrayList<>();
        names.add("Alice");
        names.add("Bob");
        names.add("Charlie");
        
        for (String name : names) {
            System.out.println("Hello, " + name);
        }
    }
}

C#:

using System;
using System.Collections.Generic;

class Program {
    static void Main(string[] args) {
        var names = new List<string> { "Alice", "Bob", "Charlie" };
        
        foreach (var name in names) {
            Console.WriteLine($"Hello, {name}");
        }
    }
}

Notice the string interpolation in C# ($"Hello, {name}") versus Java's concatenation.

IDEs for C# Development

The primary IDEs for C# development include:

• Visual Studio: Microsoft's flagship IDE, extremely feature-rich but Windows-focused (a Mac version exists with fewer features)
• Visual Studio Code: Lightweight, cross-platform editor with C# extensions
• JetBrains Rider: Cross-platform IDE built on IntelliJ's platform

My Recommendation: Rider

I highly recommend using JetBrains Rider for C# development. If you're coming from Java and have used IntelliJ IDEA, Rider will feel immediately familiar. It offers:

• Superior cross-platform support (Windows, macOS, Linux)
• Excellent refactoring tools and code analysis
• Built-in decompiler for exploring .NET libraries
• Better performance than Visual Studio on many machines
• Seamless Unity integration for game development
• The same intelligent code completion you know from IntelliJ

While Visual Studio is the traditional choice and has excellent features, Rider provides a more modern, responsive experience and works consistently across all platforms.

Getting Started

To begin with C#:

1. Install the .NET SDK from Microsoft's website
2. Install Rider (or your preferred IDE)
3. Create a new console application
4. Start coding!

The transition from Java to C# is smooth, and you'll quickly appreciate the language's modern features and expressive syntax. Welcome to C#!