从键盘输入一个字符，判断该字符是小写字母、大写字母、数字或其他字符，并给出相应的提示,回车结束退出数。字0~9的ASCII码为30H~39H；大写字母的ASCII码为41H~5AH；小写字母的ASCII码为61H~7AH；-Enter a character from the keyboard to determine which characters are lowercase letters, uppercase letters, numbers or other characters, and the corresponding prompt, enter the end of exit numbers. ASCII characters 0 to 9, code 30H ~ 39H　capital letters ASCII code 41H ~ 5AH　lower case ASCII code 61H ~ 7AH