hi,
i would like to know how a program written in a server sent to a client( or clients) then after solving the answer,client(clients) send the result back to server.like in a server a factorial program is written in C language,would you please guide me,how to do this.
thanks in advance

I guess you want something similar to http://setiathome.berkeley.edu. If so, the technique you're talking about is distributed computing. Right now, only OS X has a built-in framework to do it (XGrid). Otherwise, in the Windows world, you'll have to use one of the open-source frameworks described in this Wikipedia article.