C# code not present inside namespace and class

October 26, 2022

I am learning C# and came across a sample code which are as follows :

Shapes.cs

using System;

public record Position(int X, int Y);

public record Size(int Width, int Height);

public abstract record Shape(Position Position, Size Size)
{
    public void Draw() => DisplayShape();

    protected virtual void DisplayShape()
    {
        Console.WriteLine($"Shape with {Position} and {Size}");
    }
}

ConcreteShapes.cs

using System;

public record Rectangle(Position Position, Size Size) : Shape(Position, Size)
{
    protected override void DisplayShape()
    {
        Console.WriteLine($"Rectangle at position {Position} with size {Size}");
    }
}

public record Ellipse(Position Position, Size Size) : Shape(Position, Size)
{
    protected override void DisplayShape()
    {
        Console.WriteLine($"Ellipse at position {Position} with size {Size}");
    }
}

Program.cs

Rectangle r1 = new(new Position(33, 22), new Size(200, 100));
Rectangle r2 = r1 with { Position = new Position(100, 22) };
Ellipse e1 = new(new Position(122, 200), new Size(40, 20));

DisplayShapes(r1, r2, e1);

void DisplayShapes(params Shape[] shapes)
{
    foreach (var shape in shapes)
    {
        shape.Draw();
    }
}

Project structure :

Question :

When I build the project and run the the project with the below command :

dotnet run --project .\RecordsInheritance\RecordsInheritance.csproj

I am getting output which i.e. DisplayShapes method is getting called and output is displayed.
The C# code in Program.cs is not wrapped inside a namespace and a class and yet it is getting executed correctly like a javascript code.
Can someone explain me how this code is getting executed correctly as the code is not wrapped inside a class and there is no public static method as well ?