Is it possible to format C++ code with VIM?

Question

I am rather new to VIM. I got some source code and this is a mess. At a first sight I would like at least to get a clear and organised view of the code, so I like to get it

Answer 1

While vim is a true Swiss-knife I still prefer external tools for some jobs. This approach is some times much more intuitive and easy to remember than using the built-in equivalent.

In the case of indenting, I filter the whole file buffer through astyle. The astyle parameters are much easier to grasp in a couple of minutes, especially if you are not a vim guru. Also astyle provides much more flexibility in fine-tuning the output.

First install astyle:
# apt-get install astyle

Then inside vim:
:%!astyle (simple case - astyle default mode is C/C++)
or
:%!astyle --mode=c --style=ansi -s2 (ansi C++ style, use two spaces per indent level)
or
:1,40!astyle --mode=c --style=ansi (ansi C++ style, filter only lines 1-40)