C#分別用前序走訪、中序遍曆和後序遍曆列印二叉樹

C#分別用前序走訪、中序遍曆和後序遍曆列印二叉樹

public class BinaryTreeNode{    public BinaryTreeNode Left { get; set; }      public BinaryTreeNode Right { get; set; }      public int Data { get; set; }      public BinaryTreeNode(int data)    {        this.Data = data;    }}      public enum TreeTraversal    {        PREORDER,        INORDER,        POSTORDER    }      public void PrintTree(BinaryTreeNode root, TreeTraversal treeTraversal)    {        Action printValue = delegate(int v)        {            Console.Write(v + " ");        };              switch (treeTraversal)        {            case TreeTraversal.PREORDER:                PreOrderTraversal(printValue, root);                break;            case TreeTraversal.INORDER:                InOrderTraversal(printValue, root);                break;            case TreeTraversal.POSTORDER:                PostOrderTraversal(printValue, root);                break;            default: break;        }    }      public void PreOrderTraversal(Action action, BinaryTreeNode root)    {        if (root == null)            return;          action(root.Data);        PreOrderTraversal(action, root.Left);        PreOrderTraversal(action, root.Right);    }      public void InOrderTraversal(Action action, BinaryTreeNode root)    {        if (root == null)            return;          InOrderTraversal(action, root.Left);        action(root.Data);        InOrderTraversal(action, root.Right);    }      public void PostOrderTraversal(Action action, BinaryTreeNode root)    {        if (root == null)            return;          PostOrderTraversal(action, root.Left);        PostOrderTraversal(action, root.Right);        action(root.Data);    }

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