🔷 .NET / Mono C# Runtime

Free Online C# Compiler

Write and compile .NET C# code online with Mono / Roslyn compiler engine, LINQ support, and Monaco IDE editor.

Overview of C# (.NET) Compiler

C# is a modern, object-oriented, strongly-typed programming language developed by Microsoft for enterprise cloud applications, Unity game development, Web APIs, and desktop software. Our Online C# Compiler enables you to write, compile, and execute C# code online without installing Visual Studio or .NET SDK.

How to Use the C# (.NET) Compiler

  1. Write your C# class code inside the editor.
  2. Ensure Main method exists: static void Main().
  3. Click green ▶ Run Code button to compile via Roslyn/Mono.
  4. Inspect output in the terminal.

🧪 Tested Code Examples (C# (.NET))

Example 1: Hello World & C# String Formatting

using System;

class Program {
    static void Main() {
        Console.WriteLine("Hello, World from Online C# Compiler!");
        
        string name = "Developer";
        Console.WriteLine($"Welcome, {name}!");
    }
}
Expected Output: 
Hello, World from Online C# Compiler!
Welcome, Developer!

Code Explanation: Console.WriteLine prints formatted strings using C# string interpolation ($"...").

💡 Try modifying these examples and execute them directly in the compiler editor above!

🛠️ Common C# (.NET) Compiler Errors & Fixes

⚠️ CS0103: The name does not exist in current context

Cause: Misspelled variable or missing using System; namespace.

How to Fix: Add using System; at top of file.

Frequently Asked Questions (FAQ)

Q: Is LINQ supported in this C# compiler?

Yes! System.Linq and standard C# collections are fully supported.

Q: Do I need Visual Studio installed on my computer?

No setup required. Everything runs in browser.