Converting C source to C++

Question

How would you go about converting a reasonably large (>300K), fairly mature C codebase to C++?

The kind of C I have in mind is split into files roughly corresponding to

Answer 1

Here's what I would do:

• Since the code is 20 years old, scrap down the parser/syntax analyzer and replace it with one of the newer lex/yacc/bison(or anything similar) etc based C++ code, much more maintainable and easier to understand. Faster to develop too if you have a BNF handy.
• Once this is retrofitted to the old code, start wrapping modules into classes. Replace global/shared variables with interfaces.
• Now what you have will be a compiler in C++ (not quite though).
• Draw a class diagram of all the classes in your system, and see how they are communicating.
• Draw another one using the same classes and see how they ought to communicate.
• Refactor the code to transform the first diagram to the second. (this might be messy and tricky)
• Remember to use C++ code for all new code added.
• If you have some time left, try replacing data structures one by one to use the more standardized STL or Boost.