C# 二叉树遍历

class Program
    {
        static void Main( string[ ] args )
        {
            BinarySearcharTree nums = new BinarySearcharTree( );
            nums.Insert( 3 );
            nums.Insert( 2 );
            nums.Insert( 3 );
            nums.Insert( 4 );
            nums.Insert( 5 );
            nums.Insert( 6 );
            Console.WriteLine( "中序遍历" );
            nums.InOrder( nums.root );
            Console.WriteLine( );

            Console.WriteLine( "前序遍历" );
            nums.PreOrder( nums.root );
            Console.WriteLine( );

            Console.WriteLine( "后序遍历");
            nums.PostOrder( nums.root );
        }

        public class Node
        {
            public int data;
            public Node NodeLeft { get; set; }
            public Node NodeRight { get; set; }

            public void DisplayNode( )
            {
                Console.Write( data + " " );
            }

        }

        public class BinarySearcharTree
        {
            public Node root;
            public BinarySearcharTree( )
            {
                root = null;
            }

            /// <summary>
            /// 插入节点
            /// </summary>
            /// <param name="i">要插入的结点值</param>
            public void Insert( int i )
            {
                Node newNode = new Node( );
                newNode.data = i;
                if ( root == null )
                {
                    root = newNode;
                }
                else
                {
                    Node current = root;
                    Node parent;

                    while ( true )
                    {
                        parent = current;
                        if ( i < current.data )
                        {
                            current = current.NodeLeft;
                            if ( current == null )
                            {
                                parent.NodeLeft = newNode;
                                break;
                            }
                        }
                        else
                        {
                            current = current.NodeRight;
                            if ( current == null )
                            {
                                parent.NodeRight = newNode;
                                break;
                            }
                        }
                    }
                }
            }

            /// <summary>
            /// 中序遍历
            /// </summary>
            /// <param name="theRoot"></param>
            public void InOrder( Node theRoot )
            {
                if ( !( theRoot == null ) )
                {
                    InOrder( theRoot.NodeLeft );
                    theRoot.DisplayNode( );
                    InOrder( theRoot.NodeRight );
                }
            }

            /// <summary>
            /// 前序遍历
            /// </summary>
            /// <param name="theRoot"></param>
            public void PreOrder( Node theRoot )
            {
                if ( !( theRoot == null ) )
                {
                    theRoot.DisplayNode( );
                    PreOrder( theRoot.NodeLeft );
                    PreOrder( theRoot.NodeRight );
                }
            }

            /// <summary>
            /// 后序遍历
            /// </summary>
            /// <param name="theRoot"></param>
            public void PostOrder( Node theRoot )
            {
                if ( !( theRoot == null ) )
                {
                    PreOrder( theRoot.NodeLeft );
                    PreOrder( theRoot.NodeRight );
                    theRoot.DisplayNode( );
                }
            }
        }
    }