I suppose that you mean FastCGI, not FCGI (but Googling on FCGI gives you FastCGI immediately, so you should know that).
Googling for Fastcgi C++ gives immediately a lot of examples and good libraries. I'm very surprised you are struggling for an entire week. In particular:
- fastcgipp is a C++ library for FastCGI, and it has several examples inside.
- wt is a C++ library to write self-contained C++ web servers and has a good FastCGI mode. There are many examples inside.
- CGI on SourceForge is also a FastCgi capable library
- This old question on StackOverflow is relevant
- fastcgi-app is also interesting.
- etc...
You really should better use search engines. If you are really struggling for a whole week on something that simple, you'll have trouble making any FastCGI applications. It is very surprising that by a single Google search I found dozens of relevant answers in a minute, and that you had to work an entire week without success.