Someone is corona positive and stay at the same building with us can we be affected ?

Basics: The virus passes in droplets from a cough or saliva, If you remain 6 or more feet away from any infected person & any contact remains brief, I don't see any risk. Wash hands regularly.

Maybe: Are you able to maintain good social distancing from that person? If yes, it isn't likely that person would infect you.Wash hands often with warm water & soap for at least 20 seconds. Avoid touching eyes, nose or mouth unless hands have just been washed. Use a face covering or mask when in public. Practice social distancing – stay at least 6 feet from others (outside of family you live with).