Tree data structure in C#

Question

I was looking for a tree or graph data structure in C# but I guess there isn\'t one provided. An Extensive Examination of Data Structures Using C# 2.0 explains a bit about w

Answer 1

Here's my own:

class Program
{
    static void Main(string[] args)
    {
        var tree = new Tree()
            .Begin("Fastfood")
                .Begin("Pizza")
                    .Add("Margherita")
                    .Add("Marinara")
                .End()
                .Begin("Burger")
                    .Add("Cheese burger")
                    .Add("Chili burger")
                    .Add("Rice burger")
                .End()
            .End();

        tree.Nodes.ForEach(p => PrintNode(p, 0));
        Console.ReadKey();
    }

    static void PrintNode(TreeNode node, int level)
    {
        Console.WriteLine("{0}{1}", new string(' ', level * 3), node.Value);
        level++;
        node.Children.ForEach(p => PrintNode(p, level));
    }
}

public class Tree
{
    private Stack> m_Stack = new Stack>();

    public List> Nodes { get; } = new List>();

    public Tree Begin(T val)
    {
        if (m_Stack.Count == 0)
        {
            var node = new TreeNode(val, null);
            Nodes.Add(node);
            m_Stack.Push(node);
        }
        else
        {
            var node = m_Stack.Peek().Add(val);
            m_Stack.Push(node);
        }

        return this;
    }

    public Tree Add(T val)
    {
        m_Stack.Peek().Add(val);
        return this;
    }

    public Tree End()
    {
        m_Stack.Pop();
        return this;
    }
}

public class TreeNode
{
    public T Value { get; }
    public TreeNode Parent { get; }
    public List> Children { get; }

    public TreeNode(T val, TreeNode parent)
    {
        Value = val;
        Parent = parent;
        Children = new List>();
    }

    public TreeNode Add(T val)
    {
        var node = new TreeNode(val, this);
        Children.Add(node);
        return node;
    }
}

Output:

Fastfood
   Pizza
      Margherita
      Marinara
   Burger
      Cheese burger
      Chili burger
      Rice burger