Welcome to XCODX Online Compiler
Quick Start:
Ctrl+Enter Run code
Ctrl+S Save / Download
Ctrl+L Clear output
Select a language and start coding.
Modern .NET is Microsoft's open-source, cross-platform successor to the old Windows-only .NET Framework, first shipped as .NET Core in 2016 and unified under the single “.NET” name from .NET 5 onward. It ships on a yearly cadence — .NET 10 arrived in November 2025 as a long-term-support release alongside C# 14 — and each version trims boilerplate with features like records, pattern matching, primary constructors, collection expressions, and top-level statements that let a file start executing without a class or Main method. Stack Overflow, Bing, and large parts of Azure run on it, and it regularly posts top-tier numbers in TechEmpower web benchmarks. On XCODX this page targets that modern .NET runtime rather than the Mono compiler behind the plain C# page, so top-level statements and the newest syntax compile as written. Your code runs as a console program wired to a live terminal, and the exact runtime version is printed in the badge above the editor.
// Top-level statements: no class or Main() needed on modern .NET
Console.Write("Enter a word: ");
string word = Console.ReadLine() ?? "";
string clean = new string(word.ToLower().Where(char.IsLetter).ToArray());
string reversed = new string(clean.Reverse().ToArray());
var result = new Palindrome(word, clean == reversed);
Console.WriteLine(result.IsSame
? $"\"{result.Text}\" reads the same both ways."
: $"\"{result.Text}\" does not.");
// Records and pattern matching are core to modern C#
record Palindrome(string Text, bool IsSame);The draw here is trying the current C# language surface — records, switch expressions, collection expressions, nullable reference types, target-typed new — the day you read about it, with no Visual Studio solution or SDK install between you and the compiler. Choose this page over the Mono-based C# page when you want modern .NET behavior specifically: top-level statements, the newest syntax, and the same runtime family that ASP.NET Core and Azure ship on, which makes it well suited to .NET-stack interview prep and to university courses that standardized on cross-platform .NET. It is a good scratchpad for console logic, LINQ questions, and DateTime or string-formatting edge cases. It is a poor fit for the things .NET is known for in production — ASP.NET endpoints, Blazor or MAUI interfaces, and database work — because the sandbox has no network, no open ports, and no GUI.
No. The runtime is a cloud sandbox with no package manager and no network, so NuGet, dotnet add package, and dotnet restore all fail. You still get the complete .NET Base Class Library — System, System.Linq, System.Collections.Generic, System.Text.Json, regular expressions and more — but no third-party libraries. Any code that depends on an external NuGet package will not build.
Console.ReadLine() reads one line from standard input and returns it as a string, so wrap it in int.TryParse or int.Parse when you need a number. The live terminal streams what you type and pauses at each prompt, or you can paste every line into the Stdin Box before running. ReadLine returns null once the stream ends, which you signal with Ctrl+D.
Yes, and that is the main reason to use this page instead of the Mono-based C# page. Modern .NET supports top-level statements, so a file can begin executing with bare statements while the compiler synthesizes the entry point. Records, pattern matching, target-typed new, and interpolated strings all compile too; if a very new preview feature is rejected, the error names the language version the runtime accepts.
The exact version is shown in the badge above the editor and is the source of truth for what will compile. This page runs on the modern, cross-platform .NET line (the successor to .NET Core), not Windows-only .NET Framework or Mono. Because language features are tied to the compiler version, treat a feature that fails to compile as a signal to check the badge rather than your syntax.
Both run the same C# language, but on different runtimes. The plain C# page compiles with Mono, which is conservative about brand-new syntax, while this page targets modern .NET where top-level statements and the latest language features work. If a snippet compiles on one page but not the other, that runtime difference is usually why.
No. The sandbox executes console programs only, so there is no web server, no port binding, and no browser for Blazor. There is also no network, so HttpClient requests and database connections fail, and the filesystem is wiped after each run. Use the page for console logic, algorithms, and Base Class Library features rather than web or desktop scenarios.
main.cstext/x-csharpConsole.ReadLine()using System;
class Program {
static void Main() {
Console.WriteLine("Hello from C#.NET!");
}
}Compiler banner lines from the .NET SDK (restore progress, build summary, elapsed time) are stripped so the pane shows program output only.