Using/Mixing C in C++ code?

Question

Is using C in C++ bad?

Many people have told me that using C in C++ is bad because it\'s not as safe, and it requires more memory management. I keep telling them tha

Answer 1

regrading the argument over std::string vs char *.

std::string is not going to be slower that char * (for heap char*); many implementations are much faster because they use private memory pool. And anyway the robustness of std::string far outweighs any (unlikely) perf hit

Answer 2

Well, I'm in a strange situation. I am working on a system that is supposed to be in C++ (C++ compiler is used and term C++ is used), but everything is written in C. This is very frustrating, because it is getting to a point where I have to 'prove' C++ is better to use than C, even though we are coding in C++. It was all hell when I introduced std::string. My take on it is that everything now is starting to get cluttered (mixing of C and C++). There are rare instances of error handling. In fact, I think I can count 3 system wide try-catch statements. The code is messy, memory leaks are prominent and finding an error is a needle in a haystack. There are hundreds of lines of code that can be replaced by C++ functions. I'd say writing the code is more efficient, cleaner and easier to understand.

From my experience, yes of course you can mix C and C++. You can pretty much do whatever you want, but maintaining, debugging and actually figuring out what's going on becomes a problem. It's easy to say you're going to clean-up your memory allocations, but maybe someone else uses your code and doesn't. Maybe you forget to do it and you waste hours on finding silly bugs, instead of using that time to do something productive. I don't even think there should be an argument. When you do C++, do C++. When you do C, do C.

Answer 3

If your'e talking about techniques, I'd be careful to say that doing the above is okay.

Writing C++ programs using C-style program organization techniques will likely result in lots of maintainability issues. In general, the programmer is ignoring many of the benefits that an object-oriented language provides. Simply because much of C syntax is valid C++ and many coding techniques transfer does not mean you should do them in C++.

That said, using C functions and things isn't a problem, so long as your'e careful about their use. In some cases, you have to.

Answer 4

The better question here is, why use C? The performance? Firstly, I believe that there is no measurable performance difference for a program with the same function. Secondly, you would have to profile and prove that for your specific case, C++ is slower. Thirdly, you're giving up a huge quantity of application security by using C instead of C++.

Answer 5

Yes it's bad to mix C and C++, any the reason has nothing to do with performance or security:

It is bad cause of a maintainability:
* a C++ programmer expects all code to behave like C++.
* a C programmer expects all code to behave like C.

So when you mix C++ and C, you break both programmers expectations on how things should work.

Answer 6

My strong belief is that your question doesn't have to do with C or C++ at all. Your question is about trading dubious efficiency for safety. Yes, C can be more efficient. But how much more efficient? And what do you pay for that? These are the questions you should answer. In most cases string vs. const char* overhead is unnoticeable. If you are developing an efficiency-extremely-critical application, then why not code it in C in the first place?