用huffman编码实现对文件的压缩以及解压。其中有四个功能，分别用-f、-d等参数，压缩文件为txz文件、原文件规定问txt文件-use the Huffman coding　the file compression and decompression. Of these, four features were used-f,-d and other parameters, compressed file txz document, the provisions of the original file txt file question