Online C# Compiler
Write, compile, run, and debug C# code online in a full-featured browser IDE. Work with multiple files, save your workspace, and share or collaborate in real time.
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🔷 About This C# / .NET Online Executor
The CodeUtility C# Executor lets you write and run real C# code directly in your browser - no installation, Visual Studio setup, or .NET SDK required. It’s powered by a secure sandbox that supports the .NET runtime and modern C# language versions, including C# 9 and later.
This tool uses dotnet-script under the hood to compile and execute your code with true .NET behavior, allowing you to experiment with both basic and advanced C# features like LINQ, async/await, pattern matching, and generics.
You can test simple scripts, functions, and logic flows, or explore concepts like classes, structs, inheritance, and interfaces - all in a clean, distraction-free coding environment.
Whether you’re learning C#, testing algorithms, or experimenting with .NET features, the CodeUtility C# Executor gives you a fast, secure, and reliable way to run C# code instantly from any browser.
Use a multi-file editor, an isolated execution terminal, runtime-specific libraries, persistent workspaces, sharing, and real-time collaboration from the same executor.
How to use this executor?
Choose a runtime, open or create a file, write your code, and select Run. Output appears in the terminal, while signed-in users can keep files in a workspace, install libraries, and collaborate through shares.
- Select a version and edit the current file or open another workspace file.
- Run the code, provide input in the terminal when requested, and review saved run history.
- Use libraries, workspace tools, sharing, and chat when your task needs more than one snippet.
💡 C# Basics & Examples You Can Try Above
1. Declaring Variables and Constants
C# uses strongly-typed variable declarations. Use const for compile-time constants and readonly for runtime constants.
int age = 30;
double pi = 3.14159;
char grade = 'A';
string name = "Alice";
bool isActive = true;
// Constants
const int MaxUsers = 100;
const string Company = "CodeUtility";2. Conditionals (if / switch)
Use if, else if, and switch for control flow.
int x = 2;
if (x == 1)
{
Console.WriteLine("One");
}
else if (x == 2)
{
Console.WriteLine("Two");
}
else
{
Console.WriteLine("Other");
}
switch (x)
{
case 1:
Console.WriteLine("One");
break;
case 2:
Console.WriteLine("Two");
break;
default:
Console.WriteLine("Other");
break;
}3. Loops
C# supports for, while, and foreach loops.
for (int i = 0; i < 3; i++)
{
Console.WriteLine(i);
}
int n = 3;
while (n > 0)
{
Console.WriteLine(n);
n--;
}4. Arrays
Arrays store fixed-size collections of elements of the same type.
int[] numbers = { 10, 20, 30 };
Console.WriteLine(numbers[1]);5. List Manipulation
Use List<T> for dynamic collections.
List<int> nums = new List<int> { 1, 2, 3 };
nums.Add(4);
nums.Remove(2);
foreach (int n in nums)
{
Console.Write(n + " ");
}6. Console Input/Output
Use Console.WriteLine and Console.ReadLine for basic I/O.
Console.Write("Enter your name: ");
string name = Console.ReadLine();
Console.WriteLine($"Hello, {name}!");7. Functions
Define methods using a return type, name, and parameters.
int Add(int a, int b)
{
return a + b;
}
Console.WriteLine(Add(3, 4));8. Dictionaries
Dictionary<TKey, TValue> stores key-value pairs.
Dictionary<string, int> ages = new Dictionary<string, int>();
ages["Alice"] = 30;
Console.WriteLine(ages["Alice"]);9. Exception Handling
Handle runtime errors using try, catch, and finally.
try
{
throw new Exception("Something went wrong");
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}10. File I/O
Use File and StreamReader/StreamWriter for file operations.
File.WriteAllText("file.txt", "Hello File");
string text = File.ReadAllText("file.txt");
Console.WriteLine(text);11. String Manipulation
C# strings support methods like Length, Substring, Contains.
string message = "Hello World";
Console.WriteLine(message.Length);
Console.WriteLine(message.Substring(0, 5));
Console.WriteLine(message.Contains("World"));12. Classes & Objects
C# supports object-oriented programming through classes and objects.
class Person
{
public string Name;
public Person(string name) => Name = name;
public void Greet() => Console.WriteLine($"Hi, I'm {Name}");
}
Person p = new Person("Alice");
p.Greet();