文件操作与字符处理，统计文本文件“case1.in”中的文章每个单词出现的次数（按出现次数由多到少的顺序输出，次数相同时按字典顺序输出，不足5个单词时，按序输出全部单词）-File manipulation and character processing, statistical text file " case1.in"　in the article the number of occurrences of each word (number of occurrences by the order from largest to smallest output, frequency output of the same lexicographically less than five words, press Sequence output all the words)