programming-examples/c-sharp/DataStructures/C# Program to Implement Binary Search Tree using Linked List.cs

/*
 * C# Program to Implement Binary Search Tree using Linked List
 */
using System;
using System.Collections.Generic;
using System.Text;
namespace TreeSort
{
class Node
{
    public int item;
    public Node leftc;
    public Node rightc;
    public void display()
    {
        Console.Write("[");
        Console.Write(item);
        Console.Write("]");
    }
}
class Tree
{
    public Node root;
    public Tree()
    {
        root = null;
    }
    public Node ReturnRoot()
    {
        return root;
    }
    public void Insert(int id)
    {
        Node newNode = new Node();
        newNode.item = id;
        if (root == null)
            root = newNode;
        else
            {
                Node current = root;
                Node parent;
                while (true)
                    {
                        parent = current;
                        if (id < current.item)
                            {
                                current = current.leftc;
                                if (current == null)
                                    {
                                        parent.leftc = newNode;
                                        return;
                                    }
                            }
                        else
                            {
                                current = current.rightc;
                                if (current == null)
                                    {
                                        parent.rightc = newNode;
                                        return;
                                    }
                            }
                    }
            }
    }
    public void Preorder(Node Root)
    {
        if (Root != null)
            {
                Console.Write(Root.item + " ");
                Preorder(Root.leftc);
                Preorder(Root.rightc);
            }
    }
    public void Inorder(Node Root)
    {
        if (Root != null)
            {
                Inorder(Root.leftc);
                Console.Write(Root.item + " ");
                Inorder(Root.rightc);
            }
    }
    public void Postorder(Node Root)
    {
        if (Root != null)
            {
                Postorder(Root.leftc);
                Postorder(Root.rightc);
                Console.Write(Root.item + " ");
            }
    }
}
class Program
{
    static void Main(string[] args)
    {
        Tree theTree = new Tree();
        theTree.Insert(20);
        theTree.Insert(25);
        theTree.Insert(45);
        theTree.Insert(15);
        theTree.Insert(67);
        theTree.Insert(43);
        theTree.Insert(80);
        theTree.Insert(33);
        theTree.Insert(67);
        theTree.Insert(99);
        theTree.Insert(91);
        Console.WriteLine("Inorder Traversal : ");
        theTree.Inorder(theTree.ReturnRoot());
        Console.WriteLine(" ");
        Console.WriteLine();
        Console.WriteLine("Preorder Traversal : ");
        theTree.Preorder(theTree.ReturnRoot());
        Console.WriteLine(" ");
        Console.WriteLine();
        Console.WriteLine("Postorder Traversal : ");
        theTree.Postorder(theTree.ReturnRoot());
        Console.WriteLine(" ");
        Console.ReadLine();
    }
}
}

/*
Inorder Traversal :
15  20  25  33  43  45  67  67  80  91  99
Preorder Traversal :
20  15  25  45  43  33  67  80  67  99  91
Postorder Traversal :
15  33  43  67  91  99  80  67  45  25  20