Cognizant Programmer Analyst Trainee interview questions

I gave AMCAT in October 2012 and got an interview call from Cognizant this year in January on the 27th. My interview date was set on 29th January, 8 am at Kolkata IT Park Gangapur. First, our xeroxed documents were arranged and then we were called one-by-one for the interview. It was a one-to-one season. There was no GD. Questions asked: 1. Introduce yourself 2. Why did you apply to this? 3. C program to swap digits of a number ex. 64 to 46 4. What is sampling? 5. Difference between microprocessor and micro-controller I was able to answer the electronics parts but was stumped on the C program and the first two HR questions.