C#分別用前序遍歷、中序遍歷和后序遍歷打印二叉樹

C#分別用前序遍歷、中序遍歷和后序遍歷打印二叉樹

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<int> 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<int> action, BinaryTreeNode root)
{
    if (root == null)
        return;

    action(root.Data);
    PreOrderTraversal(action, root.Left);
    PreOrderTraversal(action, root.Right);
}

public void InOrderTraversal(Action<int> action, BinaryTreeNode root)
{
    if (root == null)
        return;

    InOrderTraversal(action, root.Left);
    action(root.Data);
    InOrderTraversal(action, root.Right);
}

public void PostOrderTraversal(Action<int> action, BinaryTreeNode root)
{
    if (root == null)
        return;

    PostOrderTraversal(action, root.Left);
    PostOrderTraversal(action, root.Right);
    action(root.Data);
}      </pre>