画出一棵二叉树，写出按照initial()函数建立该二叉树的字符序列。编写一个程序能建立一棵二叉树，并求所有叶子及结点总数。-Draw a binary tree, write in accordance with the initial () function to establish the sequence of characters of the binary tree. Write a program to establish a binary tree, and ask all the leaves and the total number of nodes.