单词处理，根据读入的文件，统计文件中纯英文字母组成的单词，并统计该单词出现的次数，并且输出到指定文件中，每行显示一个单词和出现次数，并用“，”隔开-Word processing, according to read the files, Statistics file letter words in plain English, and statistics the number of occurrences of the word, and the output to the specified file, and each line shows the number of occurrences of a word and use " ,"　separated