二叉树操作,掌握指针变量的含义，二叉树的结构特征，以及各种存储结构的特点及使用范围；指针类型描述、访问和处理二叉树的运算。程序1： 按先序次序输入二叉树中结点的值（一个字符），`0`表示空树，生成二叉树的二叉链表存储结构， a为指向根结点的指针。然后按中序顺序遍历二叉树。算法思想：先访问左子树,再访问根结点,最后访问右子树。-binary tree operation, grasp the meaning indicator variables, binary tree structure, and the various characteristics of the memory structure and scope of use; Descr iption pointer types, visits and handling binary tree arithmetic. Procedure 1 : first order input sequence binary tree node values (a character), `0` empty tree. Generation of two binary tree storage structure of the binary tree, a root node to point to the target. Then click the order binary tree traversal sequence. Algorithm : A visit to the left sub-tree, and then visit root node, right-final visit to the tree.