Gary, Could you send the mail to mailing list. Thanks. The function is defined as: protected virtual string FindFault(ProgramOutput output) It's virtual function, just define the default behaviour of the Tester class, the function should be override by derived class if we need to read the fault information from a file. That is, first create a derived class, such as LogfileTester, and then override the FindFault() by reading the information from the given log file name. The log file name should be set in the given Program object. We don't need to add another constructor to Program class. We can create a Program object, and then assign the LogFilename value. It should be easy enough to use it. Tao On Tue, Mar 18, 2008 at 10:03 PM, Yingzhi ZHU <yingzhizhu@xxxxxxxxx> wrote: > Hi, > > No logfile's name is given, default path should be given in the construct > function Program class. > > Regards, > Gary > > -- Dancefire Microsoft Certified Technology Specialist CCNA http://www.dancefire.org/ I'm enjoy in Operating System, Network Security and Embedded System.