一个完整的系统应具有以下功能：

（1）初始化 从终端读入一段英文字符，统计每个字符出现的频率，建立赫夫曼树，并将该树存入某文件；

（2）编码 利用建好的赫夫曼树对各字符进行编码，用列表的形式显示在屏幕上，并将编码结果存入另一文件中；

（3）解码 利用保存的赫夫曼编码，对任意输入的0，1序列能正确解码；

-A complete system should have the following functions: (1) initialize a read from the terminal and English characters, the frequency statistics for each character, the establishment of Huffman trees, and the tree into a document　(2) encoding The Huffman tree is built using the character encoding, using the list displayed on the screen, and coding the results into another file　(3) save the Huffman decoding using code, for any input 0,1 correctly decoded sequence