一棵非空二叉树可以看作是由根结点、左子树和右子树这三个基本部分组成的。如果能依次遍历这三个部分的信息，也就遍历了整个二叉树。由此得到的二叉树的遍历是按某种策略访问二叉树中的每一个结点且仅访问一次的过程。二叉树的遍历按访问根结点的先后次序不同分为前序、中序和后序三种。-A non-empty binary tree can be seen from the root node, the left subtree and right subtree consists of three basic parts. If you can turn these three sections traversing information, it traverses the entire binary tree. The thus obtained binary tree traversal strategy is based on a binary tree for each access point and the access node process only once. Binary tree traversal root-access priority sequence is divided into three different preorder, inorder and post.