5、 利用Set统计某字符串（可直接设定， 单词间用空格隔开）有多少单词，利用map统计该字符串中每个单词都出现几次。-5, using a string Set Statistics (can be set directly between words separated by spaces) the number of words, use of statistical map of the string several times each word.

使用的词频统计软件：用于英文单词词频统计，文件中给出主要的源代码-Frequency Statistics Software used: for the English word frequency statistics, the paper gives the main source code

统计输入中所有单词的出现次数，这里用二叉树这种数据结构。-Enter the number of occurrences of all words in the statistics, here with a binary tree data structure

请编写函数fun,函数的功能是：统计一行字符串中单词的个数，作为函数值返回。一行字符串在主函数中输入，规定所有单词由小写字母组成，单词中间由若干个空格隔开，一行的开始没有空格。-Please write a function fun, function is the function: Counts the number of his string of words, as a function of the value returned. His string entered in the m