Prototype.cs

namespace CompositePattern;

internal abstract class Component
{
    protected string Name;

    protected Component(string name)
    {
        Name = name;
    }

    public abstract void Add(Component c);

    public abstract void Remove(Component c);

    public abstract void Display(int depth);
}

internal class Leaf : Component
{
    public Leaf(string name) : base(name)
    {
    }

    public override void Add(Component c)
    {
        throw new System.NotImplementedException();
    }

    public override void Remove(Component c)
    {
        throw new System.NotImplementedException();
    }

    public override void Display(int depth)
    {
        Console.WriteLine($"{new string('-', depth)} {Name}");
    }
}

internal class Composite : Component
{
    private readonly List<Component> _children = new();

    public Composite(string name) : base(name)
    {
    }

    public override void Add(Component c)
    {
        _children.Add(c);
    }

    public override void Remove(Component c)
    {
        _children.Remove(c);
    }

    public override void Display(int depth)
    {
        Console.WriteLine($"{new string('-', depth)} {Name}");
        foreach (var component in _children)
        {
            component.Display(depth + 2);
        }
    }
}