从键盘上输 入一串正整数， 最后输入－1作为输入结束的标志。如输入的序列为：2，5，7，23，48，96，……，-1。请以这些正整数的值作为二叉排序树中的结点的数据场之值，建立一棵二叉排序树。注意：请采用动态存储方法保存这棵二叉排序树，事先并未知道该二叉排序树中的结点的个数。-Input from the keyboard on a string of positive integers, the last input-1 as an input symbol of the end. Such as input sequence as follows: 2,5,7,23,48,96, ... ...,-1. Please refer to these as a positive integer value of two binary sort tree nodes in the data field' s value, set up a binary sort tree. Note: please use the dynamic storage method to preserve tree binary sort tree, the prior did not know that the binary sort tree in the number of nodes.