构造一棵二叉树、释放二叉链表中各结点的存储空间、获取指向二叉树根结点的指针、前序遍历二叉树、中序遍历二叉树、后序遍历二叉树等的编程-Construct a binary tree, the release of storage space for each node in the binary list, access points to the binary tree root pointer, before traversing Binary inorder binary tree trav