Want some tools.

What kind of standard are you really looking for?

Style of code? Check for cb (C beautifier) and similar programs. Lots of editors/IDEs have this feature too.

Otherwise I cannot understand what you want.

What did Google turn up?

I searched the Coding Standard Enforcement (CSE) tools on Google, but I do not find any one is free.

Why do you need them "free"?

Is this for a hobby project or a commercial one?

Search on "C beautifier"

Look for "indent". Available free from GNU. For C, not C++.

astyle is also pretty good.

The first question is if the OP wants a tool for cleaning up the code, or a tool for nagging about badly written code.

cb does not nag.

If you want "nagging", then running the file through cb and diff'ing the "beautified" version with the original file is easy enough.

That will only check that your code is laid out sensibly (consistent indentation, brackets, etc.). While that's a worthy goal if the OP is incapable of writing well laid out code in the first place, it won't do any coding standards checking.

Lint