Microsoft Intern In Software Development Engineering interview questions

An on-campus interview followed with 3 onsite interviews, including one lunch interview. The on campus interview was easy, we talked about the projects I am doing, my professional interests and solved a designing problem, in other words, I designed a state machine. Then I got my first on-site interview. I was interviewed with Bing Ads. The first round went on pretty good, some basic problems playing with numbers and data structures. But I was a bit slow writing codes. The second round was an lunch interview, we had lunch in their dining hall and we talked about our personal interests, and the discussed about technologies I am interested in. I said knect. He asked me if I were supposed to add one function to Xbox, would I add, and we continued our conversation on how to realize this technology. Afterwards we grabbed a cup of tea and went back to his office, and solved a coding problem. The third round has two problems, both of them asked me to deal with a char string.