1)　　I：初始化（Initialization）。从终端读入字符集大小n，以及n个字符和n个权值，建立哈夫曼树，并将它存于文件hfmTree中。
2)　　E：编码（Encoding）。利用已建好的哈夫曼树（如不在内存，则从文件hfmTree中读入），对文件ToBeTran中的正文进行编码，然后将结果存入文件CodeFile中。
3)　　D：译码（Decoding）。利用已建好的哈夫曼树将文件CodeFile中的代码进行译码，结果存入文件TextFile中。(1) I: initialization (Initialization). From the terminal read into the character set size, N, and n characters and N weights, the establishment of Huffman tree, and save it in the file hfmTree.
2) E: coding (Encoding). Using the built Huffman tree (if not in memory, then read it from the file hfmTree), encode the text in the file ToBeTran, and then put the results in the file CodeFile.
3) D: decoding (Decoding). Huffman tree has been built using the file CodeFile code for decoding, the results stored in the file TextFile.)