Hello,
It seems you want to write a lexical and syntax analyzer for a given language, i.e. C--, using flex and bison.
I already helped several students in completing similar assignments using the same tools (as you mentioned) along with C and Lua as programming languages. All of these assignments were required to implement the first three stages of a compiler which required me to use different data structures such as linked lists, trees, stacks, and hash-tables to implement various constructs including a parse tree, the abstract syntax tree, and a symbol table. I would like to help you in completing your assignment also.
Additionally, it would be nice if you can provide a test suite for verifying the source code for both stages.
Feel free to reply to this proposal, if you find it useful.
Regards,
Atul Rajdhar