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 traversal, postorder binary tree traversal programming