It seems odd to me that people keep asking for C/C++ environments for Emacs. Odd because you’d think this would have settled years ago. I’m guessing that this is mostly about having an IDE environment, like Eclipse, for C++. A year ago I wrote about Átila Neves’ video on setting up a C++ environment for Emacs. Baris Yuksel also has a set of two videos on setting up a C/C++ environment with Emacs.
Tu Do has another useful resource. This time it’s a short guide that talks about and demos various packages that you can add to Emacs to build an excellent C/C++ environment. The post has several screen demos showing how the packages work. The guide is part of Do’s Emacs Mini Manual that I wrote about previously.
The whole Mini Manual is useful and worth taking a look at but if all you want is a guide to setting up a C/C++ environment, Do’s C/C++ guide is worthwhile on its own.