Is a class with only static methods preferable to a namespace?

问题

I was inspired by the comments under this question.

I didn't see any reason why a class with only static functions would be a better design than a namespace (with just functions). Any list of pros and cons of these two approaches are welcomed. It would be great with some practical examples!

回答1:

One non-stylistic difference is that you can use a class as a template parameter, but you cannot use a namespace. This is sometimes used for policy classes, like std::char_traits.

Outside of that use case, I would stick to a namespace with regular functions.

回答2:

Classes with static methods

• You can have class inside another class, you can't have namespace inside class (because it probably does not make any sense).
• They work with very ancient compilers.

Namespaces

- you can create namespace aliases

namespace io = boost::iostreams; Well, you can typedef classes, so this is moot point.

• you can import symbols to another namespaces.

  namespace mystuff { using namespace boost; }

• you can import selected symbols.

  using std::string;

• they can span over several files (very important advantage)

• inline namespaces (C++11)

Bottom line: namespaces are way to go in C++.

来源：https://stackoverflow.com/questions/16108730/is-a-class-with-only-static-methods-preferable-to-a-namespace