This implementation, Exuberant Ctags, is very nice, it even works on VMS systems. I use it all the time in combination with vim to navigate large heaps of messy C++. It turns your editor in something like a source browser. You can just 'click' on a function or class name and jump to its definition and then jump back to the original place again.

The output of ctags can be used for more things than just aiding an editor. The output is a list of imporant items in your program complete with a regular expression that can be used to find this item in the file. For C++ it even gives the relationships between classes.

With it, it is easy to write a Perl program that scans a ctags file and then shows you the class hierachy, what methods there are, or even the complexity of your code. The whole problem of parsing the code is taken care of by ctags. ctags is very useful.

Have Fun