单词的词频统计

基本功能要求：

（1）　　从文件中读出一篇英文文章，将不同的单词存入堆中，

建立相应的索引表确定各单词在堆中存储的位置及出现的次数。

（2）按出现的频率递减的次序输出。-The basic functions of word frequency statistics requirements: (1) read from a file an article in English, into the heap of different words, to establish the corresponding index table to determine the location of the word stored in the heap and the number of occurrences. (2) by decreasing the frequency of the order of output.