（2）设计：

设计一个字符串处理程序：实现字符串的整体、前缀、后缀比较；子字串定位；数字型字符转化为数字等各种功能。

设计一个正则表达式处理程序：能完成输入字串的处理—(a) 能找出各种表达形式的日期；(b) 能对指定格式的子串进行替换。-(2) design: the design of a string handler: compare the string as a whole, prefixes, suffixes　the substring positioning　numeric characters into various functions. Design a regular expression handler: to complete the processing of the input string- (a) to find out the date of a variety of forms of expression　(b) replace the substring of the specified format.