Naming: Why should named constants be all uppercase in C++/Java?

Question

I know, that for C++ and Java it is a well established naming convention, that constants should be written all uppercase, with underscores to separate words. Like this (Java

Answer 1

With uppercase constants long formulas are much easier to read, you don't have to guess which element can vary and which can not. It's of course only a convention, but helpful one.