用堆分配存储表示实现Hstring串类型的最小子集的基础上，实现串抽象数据类型的其余基本操作（不使用C语言本身提供的串函数）。参数合法性检查必须严格。

利用上述基本操作函数构造以下系统：它是一个命令解释程序，循环往复地处理用户键入的每一条命令，直至终止程序的命令为止。命令定义见“题集”P120，实现以下操作：(1)赋值、(2)求长度、(3)求子串、(4)比较、(5)KMP匹配、(6)显示。

-Achieved with heap-allocated storage foundation Hstring string type represents a minimal subset on the realization of the basic operation of the remaining string of abstract data types (do not use the C language itself provides string functions). Parameters validity check must be strictly. Constructed using the above basic operation following system functions: it is a command interpreter, ad infinitum handle each user typed a command, the command until the termination of the program so far. Command defined " title set"　P120, achieve the following: (1) assignment, (2) find the length, (3) her series, (4) comparison, (5) KMP matching, (6) display.