二叉树在非递归算法中，后序遍历难度大，很多书上只给出思想或者几段无法直接调试的代码，甚至有些书上是错的，当时我在研究的过程中，就是按着书上错误的代码绕了好半天，几预抓狂。好在最终摸索出来了-Binary Tree in non-recursive algorithm, after the preorder is difficult, given the many books just thinking or paragraphs not directly debugging code, and even on some of the books is wrong, I was in the process of the study, according to the book is error code around for ages, a few pre-crazy. Fortunately, the final fumble out