请编写一个程序，确定二叉树的特征。如：每个节点的层次，从根到该节点的枝长（路径长度），子孙的个数及祖先的个数。每个节点在前序、中序、后序中的访问的序号。-Please write a procedure to determine the characteristics of binary tree. Such as: the level of each node from the root to the node of the branch length (path length), the number of descendants and the number of ancestors. Each node in the former sequence, in order, after the preface序号visit.