使用Huffman编码进行文本加密（压缩）的一个示例程序。输入一段文字，自动建立Huffman树并生成各字符对应编码，并对编码前和编码后分别占用的空间进行计算-A sample program using Huffman code for text encryption (compression). Enter a text, program will automatically create Huffman tree and generate the corresponding character encoding, finally calculate the memories need before and after encoding respectively.