输入一个字符串，扫描该字符串，按数字、字母和特殊字符3类，把字符分类输出到屏幕，并计算其中数字字符的和，把求得的和以十进制数的形式输出到屏幕。-Enter a string, the string scanning, numbers, letters and special characters are three types of character output to the screen, and calculate one of the numeric characters, to ob

写一个MyString类,可以使用cstring(string.h)中库函数，然后编写代码使用函数-Write a MyString class, you can use the CString (string.h) in the library function, and then write code using function