C# Online Editor

Let's start with C# basics and object-oriented programming:

using System;

class Program
{
    static void Main()
    {
        // Basic output
        Console.WriteLine("Hello, C#!");

        // Variables and data types
        string name = "C# Programming";
        int number = 42;
        bool isTrue = true;
        double pi = 3.14159;

        // String interpolation
        Console.WriteLine($"Welcome to {name}!");
        Console.WriteLine($"Number: {number}, Pi: {pi:F2}");
    }
}

Our editor provides real-time execution and IntelliSense support.

Learn object-oriented programming fundamentals:

using System;

// Define a class
public class Person
{
    // Properties
    public string Name { get; set; }
    public int Age { get; set; }

    // Constructor
    public Person(string name, int age)
    {
        Name = name;
        Age = age;
    }

    // Method
    public void Greet()
    {
        Console.WriteLine($"Hello, I'm {Name} and I'm {Age} years old.");
    }
}

class Program
{
    static void Main()
    {
        // Create objects
        Person person1 = new Person("Alice", 25);
        Person person2 = new Person("Bob", 30);

        // Use objects
        person1.Greet();
        person2.Greet();
    }
}

Practice object-oriented concepts in our interactive environment.

Learn to use List, Dictionary, and other collections:

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // Working with List
        var fruits = new List<string> { "Apple", "Banana", "Orange" };
        fruits.Add("Grape");
        Console.WriteLine($"Fruits count: {fruits.Count}");

        // Iterate through list
        foreach (var fruit in fruits)
        {
            Console.WriteLine($"- {fruit}");
        }

        // Working with Dictionary
        var scores = new Dictionary<string, int>
        {
            ["Alice"] = 95,
            ["Bob"] = 87
        };
        scores["Charlie"] = 92;

        foreach (var kvp in scores)
        {
            Console.WriteLine($"{kvp.Key}: {kvp.Value}");
        }
    }
}

Practice with various collection types and operations.

Learn proper error handling patterns:

using System;

class Program
{
    static void Main()
    {
        // Basic try-catch
        try
        {
            int result = Divide(10, 0);
            Console.WriteLine($"Result: {result}");
        }
        catch (DivideByZeroException ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Unexpected error: {ex.Message}");
        }
        finally
        {
            Console.WriteLine("Cleanup code runs here.");
        }

        // Using validation
        if (TryParseInt("123", out int number))
        {
            Console.WriteLine($"Parsed number: {number}");
        }
    }

    static int Divide(int a, int b)
    {
        if (b == 0)
            throw new DivideByZeroException("Cannot divide by zero");
        return a / b;
    }

    static bool TryParseInt(string input, out int result)
    {
        return int.TryParse(input, out result);
    }
}

Practice robust error handling in our safe environment.

Master C# collections and generic programming:

using System;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // List<T>
        var fruits = new List<string> { "Apple", "Banana", "Orange" };
        fruits.Add("Mango");
        Console.WriteLine("Fruits: " + string.Join(", ", fruits));

        // Dictionary<TKey, TValue>
        var ages = new Dictionary<string, int>
        {
            ["Alice"] = 25,
            ["Bob"] = 30,
            ["Charlie"] = 35
        };

        foreach (var kvp in ages)
        {
            Console.WriteLine($"{kvp.Key} is {kvp.Value} years old");
        }

        // Generic methods
        var numbers = new List<int> { 1, 2, 3, 4, 5 };
        var doubled = ProcessList(numbers, x => x * 2);
        Console.WriteLine("Doubled: " + string.Join(", ", doubled));
    }

    static List<TResult> ProcessList<T, TResult>(List<T> input, Func<T, TResult> processor)
    {
        var result = new List<TResult>();
        foreach (var item in input)
        {
            result.Add(processor(item));
        }
        return result;
    }
}

Explore type-safe generic programming.

Master time and string operations in C#:

using System;
using System.Text;

class Program
{
    static void Main()
    {
        // DateTime operations
        DateTime now = DateTime.Now;
        DateTime future = now.AddDays(30);
        Console.WriteLine($"Current time: {now:yyyy-MM-dd HH:mm:ss}");
        Console.WriteLine($"30 days later: {future:yyyy-MM-dd}");

        // String manipulation
        string text = "  Hello, C# World!  ";
        string cleaned = text.Trim().ToUpper();
        string[] words = cleaned.Split(' ');

        Console.WriteLine($"Original: '{text}'");
        Console.WriteLine($"Cleaned: '{cleaned}'");
        Console.WriteLine($"Word count: {words.Length}");

        // StringBuilder for efficiency
        var sb = new StringBuilder();
        for (int i = 1; i <= 5; i++)
        {
            sb.AppendLine($"Line {i}: {DateTime.Now.Millisecond}");
        }
        Console.WriteLine(sb.ToString());
    }
}

Practice essential string and time operations.

Our C# editor runs C# 12+ with .NET 8+ via WASI with specific constraints:

Version & Environment:

• C# 12+ with .NET 8+ WASI support
• Memory limit: ~1GB for applications
• Console applications only

Key Limitations:

• No file I/O operations
• No network operations (HttpClient, etc.)
• No database connections
• No multi-threading or async/await
• No Task.Delay, Task.WhenAll, or threading
• No WPF/WinForms UI frameworks
• Limited reflection in AOT mode
• No unsafe code or P/Invoke
• No subprocess execution

Available Features:

// Core .NET libraries available
using System;
using System.Collections.Generic;
using System.Text;

// Collections, generics, basic .NET features supported

Focus on algorithms, data structures, and business logic.

Explore these official resources and learning materials:

Official Documentation:

• Microsoft C# Documentation - Complete C# reference
• .NET 8 Documentation - .NET platform guide
• C# Language Reference - Language specifications
• .NET API Browser - Standard library reference

Learning Resources:

• Microsoft C# Learning Path - Structured learning
• C# Coding Conventions - Style guide
• C# Programming Guide - Comprehensive guide
• C# Corner - Community tutorials and articles

Enterprise Development:

• ASP.NET Core Documentation - Web development
• Entity Framework Core - Object-relational mapping
• Azure .NET Documentation - Cloud development

These resources cover C# from basics to enterprise-level .NET development!