Welcome to HCODX Online Compiler
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Compile and run C# code online instantly with HCODX. Our free cloud-based C# compiler supports real-time execution, standard input, syntax highlighting, and code download. No installation or configuration required. Start coding in C# now.
Run C# instantly without installing any IDEs or configuring environments. Our cloud-based C# handles libraries, runtimes, and dependencies automatically so you can focus on writing code.
Whether you are studying algorithms in C#, practicing data structures in C#, or exploring functional programming, our tool provides real-time stdout/stderr feedback with interactive standard input support.
HCODX is a free online compiler and code runner: write code in your browser, execute it on a cloud sandbox, and interact with your program through a live terminal. Students use it for coursework and interview practice; developers use it to test snippets in 85+ languages without setting up a local environment.
C# powers two very different worlds at once: enterprise software across the Microsoft ecosystem, and game development, where it serves as the scripting language of Unity — the engine behind a huge share of mobile and indie games. Designed by Anders Hejlsberg (who later created TypeScript), the language pairs strong typing with conveniences like LINQ, async/await, pattern matching, and records. This page runs your C# on the Mono runtime — the battle-tested open-source implementation — inside an interactive terminal, where Console.ReadLine() suspends the program and waits for your actual keystrokes, so console exercises from a C# course or Unity tutorial run without installing Visual Studio.
using System;
using System.Linq;
class Program
{
static void Main()
{
Console.Write("Enter your name: ");
string name = Console.ReadLine();
Console.Write("Enter numbers separated by spaces: ");
int[] nums = Console.ReadLine()
.Split(' ', StringSplitOptions.RemoveEmptyEntries)
.Select(int.Parse)
.ToArray();
Console.WriteLine($"Hi {name}! You entered {nums.Length} numbers.");
Console.WriteLine($"Sum = {nums.Sum()}, Max = {nums.Max()}, Avg = {nums.Average():F2}");
}
}Complete the console-application chapters that open nearly every C# textbook and Unity learning path — input, loops, methods, classes — before graduating to MonoBehaviours and scenes, or drill LINQ queries until Select, Where, GroupBy, and Aggregate feel automatic. University courses that teach OOP in C# assign exactly the kind of single-file console programs this sandbox runs, and candidates facing C# technical screens can rehearse collection-manipulation questions with genuine stdin instead of hardcoded test values. HCODX is a free online C# editor, runner and interpreter — an IDE-grade compiler and playground to write and run code online, execute code with live output and live preview, no downloads or web server required.
It does — your program gets a live terminal, so each Console.ReadLine() halts execution until you type a line and press Enter. Console.Write prompts appear immediately beforehand, giving you the natural prompt-answer-prompt rhythm of a local console app rather than a pre-filled input form.
This page executes on Mono, an independent open-source implementation of the C# runtime with a long history (it's the lineage Unity built on). The separate C# .NET page runs Microsoft's modern cross-platform .NET. Core language behavior is the same for typical programs; choose .NET if you specifically need the newest language version's features.
Unity's engine classes (MonoBehaviour, GameObject, Transform) exist only inside the Unity editor and player, so they won't compile in a plain runtime. The valuable part you can test here is your game logic — inventory math, state machines, procedural generation algorithms — as ordinary C# classes before wiring them into components.
Your current code will be replaced with the default sample. This cannot be undone — download your code first if you want to keep it.
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