Hello guys , I am relatively new with arduino. I need your expert help on a matter of prime importance. I need to know how an arduino can communicate to the terminal (stdIn). So that the value passed by it gets accepted by another program running on the terminal. In short I want a value to be entered by my arduino to a program running on the terminal. Is that possible in anyway. Looking forward to your help. 
Yes, it is possible. The Arduino can send data to the host through the Serial functions. You can find out all about them in the on-line reference. As for the host end, that is up to you, but if you have any experience in programming I/O then you'll have no issue.
The Serial functions can be found here: Serial - Arduino Reference