How to cut off negative people from your life?

people always say that you should cut off the negative people who always demotivate you and try to dictate you according to their own thinking. But, i think practically it is very difficult, especially when those people are your friends. I am facing a same type of situation. I have a friend, who always talk negative things and whenever i meet him, i feel so depressed. I can't cut him off from my life because in past there were so many moments when he helped me in many problems. But, now i think that its time to keep him out of my life because i am a positive person and i don't like negative and depressing talk.

Story is very one sided. Are you sure you didn't contribute to the cause of such negativity? In any case, best of luck for future endeavors.