> ## Documentation Index
> Fetch the complete documentation index at: https://docs.codecrafters.io/llms.txt
> Use this file to discover all available pages before exploring further.

# C#

> Learn how to solve CodeCrafters challenges in C#

## Local development

To run the code for your challenge locally, you'll need `dotnet` installed. Our test runners use Dotnet 8.0 (as of April 2024).

The script for your challenge (like `./your_sqlite3.sh`) will automatically compile your code using `dotnet` before executing it. It'll
look something like this:

```sh theme={null}
#!/bin/sh

exec dotnet run --project . --configuration Release -- "$@"
```

## File structure

* The files for your solution are placed in the `src/` directory.
* `src/Program.cs` contains the `main` function, which is what the test runner executes.
* The `.csproj` file defines project settings, target frameworks and dependencies.

## Adding more files

You can add more files and directories to `src/`. The test runner will include them when compiling your code.

For example, if you added a file at `src/Foo.cs`, you could use it like so:

<CodeGroup>
  ```csharp src/Program.cs theme={null}
  public class Main {
      public static void Main(String[] args) {
          Foo.foo();  // calls the method foo() from Foo class in Foo.cs
      }
  }
  ```

  ```csharp src/Foo.cs theme={null}
  public class Foo {
      public static void foo() {
          System.out.println("Hello world!");
      }
  }
  ```
</CodeGroup>

By default, all classes in `src/` belong to the same namespace. This namespace is called the *project namespace*. E.g. If the project name is `MyProject`, all classes are defined under the `MyProject` namespace. This is why you can call `foo()` without importing anything.

If you want to define a class under a *different* namespace, you'll need to use the [namespace](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/namespace) keyword like this:

```csharp theme={null}
namespace AnotherNamespace {
    public class Foo {
        public static void foo(string[] args) {
            // write code here
        }
    }
}
```

Let's say you want to define the `Foo` class in `Foo.cs` under the `AnotherNamespace` namespace.

<CodeGroup>
  ```csharp src/Foo.cs theme={null}
  namespace AnotherNamespace {
      public class Foo {
          public static void foo() {
              System.out.println("Hello world!");
          }
      }
  }
  ```

  ```csharp src/Program.cs theme={null}
  using AnotherNamespace

  public class Main {
      public static void main(String[] args) {
          Foo.foo();  // Uses the foo function from Foo class defined under AnotherNamespace
      }
  }
  ```
</CodeGroup>

## Adding dependencies

You can add dependencies to your project by using `dotnet`.

For example, to add the `Newtonsoft.Json` package, run the following command in your terminal:

```bash theme={null}
dotnet add package Newtonsoft.Json
```

It will also update your `.csproj` file with the package reference:

```xml theme={null}
<ItemGroup>
  <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
</ItemGroup>
```