Comment the interface, implementation or both?

Question

I imagine that we all (when we can be bothered!) comment our interfaces. e.g.

/// 

/// Foo Interface
/// 
public interface Fo         


        

Answer 1

The interface only. Commenting both is duplication and it's likely that the two sets of comments will eventually get out of sync if the code changes. Comment the implementation with "implements MyInterface"... Things like Doxygen will generate docs that include the derived docs into the docs for the implementation anyway (if you set them up correctly).