The usage of anonymous enums

Question

What is the purpose of anonymous enum declarations such as:

enum { color = 1 };

Why not just declare int color = 1

Answer 1

One use of this is when you're doing template metaprogramming, because enum objects are not lvalues, while static const members are. It also used to be a common workaround for compilers that didn't let you initialize static integral constants in the class definition. This is explained in another question.