在从键盘上输入字符时，只要是键盘上的字符任何字符都能接受，并能统计出输入的一串字符串中各个字符出现的次数，作为构建哈夫曼树时的各叶子结点的权值。 本程序同时具有译码功能 -Character input from the keyboard, as long as any of the characters in the character on the keyboard can be accepted, and the statistics of the number of occurr