使用类模板生成与遍历二叉树：建立了一个二叉树，并以中序遍历、前序遍历和后序遍历三种方法遍历该二叉树-The use of class template generation and traversal binary tree: the establishment of a binary tree and traversal of the former sequence and post-order traversal traversal traversal of the tree in thre