"Kindly let me know what is wrong with the code. It does not seem to work "

Very right. What you posted is a code snippet and does not qualify as a complet code.

There could be a problem in your header.

There could be problem in your simulator set up or hardware setup ..

There could be so many issues - unless you describe the whole setup, commenting on what is wrong with the code alone does not help solve the problem.

Raghu