Access版本易语言树型框无限分级的使用方法源码。-Access version easy language box unlimited hierarchical tree. Zip

定义二叉链表类型，实现二叉树的基本操作：建立、先中后序遍历、层次遍历及输出。-The definition of two fork list type, two fork tree to achieve the basic operation: the establishment, the first in the order traversal, hierarchical traversal and output.