First round coding, 2nd round data structure followed by Manager round and HR Round C++ and IPC question , project related C and C ++ and technical C and C ++ and technical C and C ++ and technical

Interviewer did not have any knowledge in that area and i saw him just before interview asking his colleagues what question should he ask and what will be the answers. Later in interview he did not agree on my answers which were perfectly right. And next day i received a mail that my candidature is rejected.