Check the LAN machines up or not ?

I was always interested finding out if some machines on my LAN is powered up or not. Say whose ip are between 10.6.15.100 - 10.6.15.150. One can find it manually however it is laborious. I just wrote a quick c++ program. It works in my Ubuntu laptop. Check out the pastebin page.

http://pastebin.com/ketm0C83    <<<--- click="" code.="" for="" here="" p="">

Thanks Yo!

There is a most recent article here -- it is efficient than above.