建立二叉树，层序、先序遍历 要求能够输入树的各个结点，并能够输出用不同方法遍历的遍历序列；分别建立建立二叉树存储结构的的输入函数、输出层序遍历序列的函数、输出先序遍历序列的函数；-Establishment of a binary tree, sequence, preorder required to enter each node of the tree, and can output traversal sequences of different methods to traverse　were established to build the storage structure of binary input function, the output layer traversal sequence function, the output first function sequence preorder