using System;

​

class Node<T>

{

    public T Data;

    public Node<T> Left;

    public Node<T> Right;

    public Node(T data)

    {

        Data = data;

    }

}

​

class BinTree<T>

    where T : IComparable

{

    private Node<T> root;

    public BinTree() //creates an empty tree

    {

        root = null;

    }

​

    public BinTree(Node<T> node) //creates a tree with node as the root

    {

        root = node;

    }

​

    public void InOrder(ref string buffer)

    {

        inOrder(root, ref buffer);

    }

​

    private void inOrder(Node<T> tree, ref string buffer)

    {

        if (tree != null)

        {

            inOrder(tree.Left, ref buffer);

            buffer += tree.Data.ToString() + ",";

            inOrder(tree.Right, ref buffer);

        }

    }

​

    public void Preorder(ref string buffer)

    {

        PreOrder(root, ref buffer);

    }

​

    public void PreOrder(Node<T> tree, ref string buffer)

    {

        if (tree != null)

        {

            buffer += tree.Data.ToString() + ",";

            PreOrder(tree.Left, ref buffer);

            PreOrder(tree.Right, ref buffer);

        }

    }

​

    public void postOrder(ref string buffer)

    {

        PostOrder(root, ref buffer);

    }

​

    public void PostOrder(Node<T> tree, ref string buffer)

    {

        if (tree != null)

        {

            PostOrder(tree.Left, ref buffer);

            PostOrder(tree.Right, ref buffer);

            buffer += tree.Data.ToString() + ",";

        }

    }

}

​

public class Program

{

    public static void Main()

    {

        Node<int> root = new Node<int>(6);

        root.Left = new Node<int>(15);

        root.Left.Right = new Node<int>(654);

        BinTree<int> tree = new BinTree<int>(root);

        string buffer = "";

        tree.InOrder(ref buffer);

        System.Console.WriteLine(buffer);

    }

}