Advent of Code 2025

Solutions to Advent of Code 2025 challenges implemented in C#.

Tech Stack

• .NET 10.0 (GA)
• C# 14 with latest language features
• TUnit for testing

Project Structure

src/
  ConsoleApp/           # Main application
    Domain/             # Domain models (Dial, Safe)
    Program.cs          # Entry point
    input.txt           # Puzzle input
tests/
  ConsoleApp.Tests/     # Unit tests

Getting Started

Prerequisites

• .NET 10 SDK

Build

dotnet build

Run

dotnet run --project src/ConsoleApp/ConsoleApp.csproj

Testing

Run all tests:

dotnet test

Run tests for a specific class:

dotnet test --filter "FullyQualifiedName~SafeTests"

Run a specific test:

dotnet test --filter "FullyQualifiedName~SafeTests.Create_WithValidPosition_ShouldSetDialPosition"

Code Style

• File-scoped namespaces
• Factory pattern with static Create() methods
• C# 14 field keyword in property setters
• Modern validation with ArgumentOutOfRangeException.ThrowIfLessThan/ThrowIfGreaterThan
• Async/await patterns with TUnit

License

See LICENSE file for details.