I'd like to share a programming puzzle that I've encountered recently. The requirement was interesting and I was thinking over it. Finally, I got a way to deal with these non-conventional requirements. The requirement is something like below: 1. I need a program, which will launch another program from the command line (I mean Windows command line). I know this is not a big deal. But this requirement has two parts, which forced me to think: 1a. Once the user double clicks on the software, then a command prompt will launch and execute another program say notepad, and the command prompt will not return until the program launched (notepad) is closed by the user. 1b. If the user launches the program from an already open command prompt, then the prompt will not open another command prompt but launch another program (in this case notepad) and will not return until the launched program/process is closed. This is a relationship of parent-child. The parent is looking afte