电文编码中含有字符str={"a","b","c","d","e","f","g","h"};每种字符出现频率fnum[]={0.07,0.19,0.02,0.06,0.32,0.03,0.21,0.1},应用数据结构中二叉树的技术实现哈夫曼编码,输出每个字符对应的哈夫曼编码。