Hi this is chidamparam, i am new to micro-controller i knew the program for getting input and processing it but now i need to built a keyboard from 1-9 as show:
1 2 3
4 5 6
7 8 9
i need the circuit. i.e. any resistor or any thing else to be connected to the circuit or simply we can connect to micro-controller?

 

Hey welcome to AAC.

Did you try googling for a circuit.
Try to find key matrix circuits.
It is pretty simple.

 

The device you are referring to is called a keypad.

A quick google search using "keypad for microcontroller" provided this.
It looks pretty thorough, and well taught.

http://www.8051projects.net/keypad-interfacing/introduction.php