C#: The Professional Kitchen

Welcome to the C# language guide! If programming languages were kitchens, C# would be the clean, organized, and high-performance professional kitchen designed for building robust and scalable applications.

What is C#?

C# (pronounced "C-sharp") is a modern, object-oriented, and type-safe programming language developed by Microsoft. It runs on the .NET platform, which allows it to be used for building a wide variety of applications, from web APIs and desktop apps to powerful video games.

What is it Used For?

C# is a versatile workhorse, particularly popular in the enterprise world and game development:

• Web Development: Building high-performance backend services and web APIs with ASP.NET Core.
• Game Development: It is the primary language used for the Unity engine, which powers a huge number of games on all platforms.
• Enterprise Software: Creating robust, scalable applications for businesses.
• Windows Desktop Apps: Building native applications for the Windows desktop.

Why You Might Like C#

• Strongly Typed: C# checks your code for errors before it runs, which helps you catch bugs early and write more reliable software.
• Performance: As a compiled language, C# offers excellent performance suitable for demanding applications like games and backend services.
• Amazing Tooling: The development experience with tools like Visual Studio and VS Code with C# Dev Kit is considered best-in-class, offering powerful debugging, code completion, and project management.
• Backed by Microsoft: With the backing of a major tech company, C# has a rich ecosystem, long-term support, and a vibrant community.

Keep in Mind

While powerful, it is most at home within the .NET ecosystem, which can feel like a large world to learn at first.

A Taste of C# Syntax

Here’s a taste of what C# code looks like. It's structured and clear, designed for building maintainable applications.

// === C#: A Day at The Coder's Cafe ===
using System;
using System.Collections.Generic;

// --- Module 1: Greeting the Customer ---
Console.WriteLine("Welcome to The Coder's Cafe!");
// This is a note for the chef (a comment)
string customerName = "Anders";

// --- Module 2: Prepping the Ingredients (Data) ---
string dishName = ".NET Noodle Soup";     // string
int quantity = 1;                         // int
double pricePerDish = 16.00;              // double
bool isOrderReady = false;                // bool
string orderSummary = $"{quantity}x {dishName}"; // String Interpolation

// --- Module 3: In the Kitchen (Logic) ---
if (dishName.Contains("Soup")) {
    Console.WriteLine($"Cooking {orderSummary} in the large pot.");
} else {
    Console.WriteLine($"Cooking {orderSummary} on the stove.");
}

// --- Module 4: Handling the Full Order (Collections & Loops) ---
// A customer's complete order (List)
var customerOrderList = new List<string> { ".NET Noodle Soup", "Generic Grape Juice" };
Console.WriteLine("Processing full order:");
foreach (var item in customerOrderList) {
    Console.WriteLine($"- Adding {item} to the ticket.");
}

// A process that repeats until a condition is met (While Loop)
int soupTemp = 80;
while (soupTemp < 100) {
    Console.WriteLine($"Heating soup... now at {soupTemp}°C");
    soupTemp += 10;
}
Console.WriteLine("Soup is ready!");

// --- Module 5: The Final Bill & A Special Offer (Functions & Imports) ---
// The Random class is part of the System library, imported above.
var random = new Random();

// A standard procedure (Method/Function)
double CalculateBill(string customer, List<string> items, double totalPrice) {
    Console.WriteLine($"\n--- Bill for {customer} ---");
    foreach (var item in items) {
        Console.WriteLine($"  - {item}");
    }

    // Let's add a random promotional discount!
    int discount = random.Next(5, 21); // 5 to 20%
    Console.WriteLine($"Applying a special {discount}% discount!");
    double finalPrice = totalPrice * (1 - discount / 100.0);
    return finalPrice; // Return the calculated value
}

// A bill represented as a Dictionary (Key-Value pairs)
var orderBill = new Dictionary<string, object> {
    { "customer", customerName },
    { "items", customerOrderList },
    { "total", pricePerDish * quantity }
};

// Call the function to get the final result
double finalAmount = CalculateBill(
    (string)orderBill["customer"],
    (List<string>)orderBill["items"],
    (double)orderBill["total"]
);

Console.WriteLine($"Your final bill is {finalAmount:C}."); // :C formats as currency
Console.WriteLine($"Thank you for dining with us, {customerName}!");

Start Coding in C#

Here are the simplest ways to start, from the easiest method to the most common one.

1. In Your Browser (The Easiest Start)

This method requires no installation. You can write and run small C# programs immediately on a website.

• What to use: .NET Fiddle or Replit.
• How it works: It’s a free website with a text box. You write your C# code, click the "Run" button, and see your program's output right in the browser.
• Best for: Learning the C# syntax, testing a small piece of code, or sharing code examples.

2. On Your Computer (The Standard Way)

This is how all developers build real applications with C#. This method requires you to install the .NET SDK (Software Development Kit) from Microsoft's website (dot.net).

Running a Simple App (The Main Way)

C# is project-based. The dotnet command (which you get from the .NET SDK) creates all the files you need for a "Hello World" app.

• How to use:
  1. Open your computer's "Terminal" or "Command Prompt".
  2. Type dotnet new console -n MyFirstApp to create a new project in a folder named MyFirstApp.
  3. Go into that folder: cd MyFirstApp.
  4. Type dotnet run. This will compile and run your project.
• Best for: Building any real application, from command-line tools to web APIs.

Using an IDE for a Better Workflow

An "IDE" (Integrated Development Environment) is a powerful editor with extra features that are almost essential for C#.

• What to use:
  1. VS Code with the C# Dev Kit extension (Modern, lightweight, and works on Mac, Linux, and Windows).
  2. Visual Studio (A full-featured "powerhouse" IDE from Microsoft. It's the standard for professional Windows development and game development with Unity).
• How it works: These tools check your code for errors, auto-complete what you type, and let you run and debug your code with the click of a button.
• Best for: Building any serious project (web, desktop, or games).

Managing Project Dependencies with NuGet

This is how you add "packages" (other people's code libraries) to your project.

• What is a dependency? Most C# projects use "packages" from NuGet, which is a giant online repository of .NET libraries. These are collections of pre-written code that solve common problems.
• What tool to use: The dotnet command has built-in support for NuGet.
• How it works: You use a simple terminal command to add a new library to your project. For example: dotnet add package Newtonsoft.Json (a very popular library for working with JSON).
• Best for: All projects that use external libraries, especially for web development.