I was asked only one question in the first round. char *str="hello"; and I was asked what will happen if str[1] = 0; is executed. Our discussion started with this and spilled over all the operating system concepts, touching process management, memory management parts of the system. Discussion lasted around 1 hour. For the Later three technical rounds questions were not really difficult. Simple coding problems related to linked list, stack, tree, but with detailed thought processing with respect to code for that problem.