程序接受用户键入的一行字符（字符数不超过80个，该字符串用回车符结束），并按字母、 数字以及其他字符分类统计，然后将结果存入以letter,digit和other为名的存储单元。 -Procedures acceptable to the user typed his character (the number of characters is not more than 80, the end of the string with carriage return), and lette