Setting Up Your Advent Of Code 2025 Project A Comprehensive Guide

October 10, 2025 by StackCamp Team 66 views

Hey guys! Are you as stoked as I am for Advent of Code 2025? To make sure we're all prepped and ready to dive into those coding puzzles, let's walk through how to set up our project. Trust me, getting organized now will save you a ton of headaches later. We’re going to follow a structure similar to previous years, so if you’ve done this before, some of this will be familiar. If not, no worries – we'll take it step by step. This guide will cover everything from creating the main project folder to setting up individual files for each day’s challenge. Let's get started and make sure we're all set for an awesome coding adventure!

1. Creating the Main Project Folder

First things first, let's create the main project folder. This is where all our code and inputs for Advent of Code 2025 will live. Keeping everything organized from the start makes it way easier to navigate as the challenges roll in. You want to create a new folder named AOC.2025. Notice the naming convention here? We're following the pattern from previous years like AOC.2021, AOC.2022, and so on. This consistency helps keep things tidy if you've participated in past events or plan to in the future.

Why is this important? Think of this folder as your home base for the entire event. By keeping everything related to Advent of Code 2025 in one place, you avoid cluttering your other projects and can quickly find what you need. Plus, if you're using version control (and you should be!), this makes it simple to track your progress and revert changes if necessary. Inside this main folder, we’ll be creating subfolders and files for each day’s challenge, input data, and any supporting code. So, let's get that folder created and move on to the next step!

2. Setting Up Daily Challenge Files

Now that we've got our main project folder, it's time to set up the individual files for each day's challenge. This is where the real coding magic happens! For each day of Advent of Code (from December 1st to 25th), we're going to create a separate file. That means we'll have files named Day01.cs, Day02.cs, all the way up to Day25.cs. These files will contain the code for solving the puzzles for each respective day. Inside the AOC.2025 folder, create these files. Each file should implement a class structure similar to what we've used in previous years. This consistency makes it easier to jump between days and keep your code organized.

Here’s the basic structure you should use for each file:

namespace AOC._2025;
public class Day01 { /* ... */ }

Why this structure? Using namespaces like AOC._2025 helps prevent naming conflicts and keeps your code modular. The Day01 class (or Day02, Day03, etc.) will contain the methods and logic to solve the specific challenges for that day. This clear separation of concerns makes your code easier to read, debug, and maintain. Plus, it follows a pattern that’s worked well in the past, so we know it’s a solid approach.

3. Creating Input Files

Alright, we've got our code files set up, but what about the input data? Each Advent of Code challenge comes with a unique input file that your program needs to process. To keep things organized, we're going to create an Inputs subfolder inside our AOC.2025 folder. This is where we'll store all the input files for each day. Inside the Inputs folder, you'll create a corresponding input file for each day, named Day01.txt, Day02.txt, and so on, up to Day25.txt. These .txt files will contain the specific input data for each day’s puzzle. Make sure to download the input data from the Advent of Code website and save it into the correct file.

Why a separate folder for inputs? Think of it this way: your code is the engine, and the input data is the fuel. You don't want to mix them up! By keeping the input files separate, you ensure that your code remains clean and focused on the logic of solving the puzzle. It also makes it easier to manage different input sets if you're testing your code or working on multiple solutions. So, create that Inputs folder and fill it with the data we'll need for each day.

4. Adding Test Methods

Testing, testing, 1, 2, 3! We want to make sure our code is not just running, but running correctly. For each day’s challenge, we’ll have two parts, and we want to ensure our solutions for both are spot-on. That’s where test methods come in. In each day’s class file (Day01.cs, Day02.cs, etc.), we're going to add [Fact] test methods for Part1 and Part2. These tests will verify that our code produces the correct output for the given input. Follow the structure used in previous years to keep things consistent. This typically involves using a testing framework like xUnit.net, which allows us to easily write and run tests.

Here’s a basic example of what the test methods might look like:

using Xunit;

namespace AOC._2025;

public class Day01
{
    [Fact]
    public void Part1()
    {
        // Your test logic for Part 1 here
    }

    [Fact]
    public void Part2()
    {
        // Your test logic for Part 2 here
    }
}

Why are tests so important? Imagine solving a puzzle, thinking you've got the right answer, and then… nope! Tests help us avoid that frustration. By writing tests, we can quickly and automatically check our solutions against known inputs and ensure they’re correct. This is especially crucial for Advent of Code, where the puzzles can be complex, and even a small mistake can lead to the wrong answer. So, let’s add those test methods and make sure our code is rock solid!

5. Including Files in the Project

Okay, we've created our folders and files, but we need to make sure they're actually included in our project! This step ensures that your IDE (like Visual Studio) and build tools recognize the new files and folders we've created. We need to include the new AOC.2025 folder and all its contents (the daily challenge files and the Inputs subfolder) in your solution/project file. This usually involves modifying the .csproj file for C# projects. You might also need to update any build or test configuration settings to include the new files.

How do you do this? In Visual Studio, for example, you can right-click on your project in the Solution Explorer, select "Add," and then "Existing Folder" to include the AOC.2025 folder. Make sure to also include all the files within that folder. You may also need to manually edit the .csproj file to ensure that all files are included in the build process. This might involve adding `<Compile Include=