Managed, Unmanaged, Native : What Kind of Code is This?

http://diehard98.tistory.com/entry/Managed-%EC%BD%94%EB%93%9C-Unmanaged-%EC%BD%94%EB%93%9C-%EA%B7%B8%EB%A6%AC%EA%B3%A0-Native-%EC%BD%94%EB%93%9C%EC%97%90-%EB%8C%80%ED%95%9C-%EC%9D%B4%EC%95%BC%EA%B8%B0