[Scip] Design choices

[Stefan Lörwald]

Hi Thorsten,

 > With 20 years of experience I can tell that this is definitely not true.
 > Apart from this you can get pretty much the same amount of data
 > encapsulation and
 > abstraction in C, though the effort might be somewhat higher.
 > And even to precisely tell what a given piece of C++ code does is so
 > much more
 > complicated than simple C.

I'm sorry to hear that, but chances are that you've been using C++ wrong.

>> This also enables further
 >> optimizations, e.g. by having some methods declared const which means
that
 >> the method does not modify the object (bitwise const, pre-C++11) or is
 >> const in the sense of thread-safety (inherently synchronized, >=C++11).
 >
 > maybe in C++ 11. Let us dream on.

C++11 is reality. Why dream?

 > Fortran is still optimizing better :-D (for bad reasons, but anyway)

Fortran hasn't been part of this discussion, but well yes, maybe it does a
lot more optimization, I don't know. So what?

>> Templates reduce code duplication (with free maintainability bonus!
>
> Have you every looked at polymake? Look there and tell me about
> the maintainability bonus :-)

I didn't say you'd automagically (sic!) get good code with C++. You don't
even need to include a different project into this discussion. The TSP
example in the SCIP suite is enough. Templates give you the possibility of
maintainable and fast code, but as with everything, you can abuse them.

Just for fun though: How about a little programming challenge? For two
arbitrary built-in type such as integers or floats, check if a value of the
first type is representable as the second type.
I'd like to see you try getting a efficient implementation with C. Problem:
C lacks templates. C++ can do most of these checks with at most two
assembly instructions (floats are a bit more tricky).

This is how a C++ solution could look like: http://ideone.com/lBxnAW

Note that there is no truth table or similar things. Most of the type
checks and comparisons are done at compile time. This is the beauty of
C++11 and templates: Highly flexible code, short code, readable code, most
efficient code.

I'd be extremely intrigued to see your implementation in C.

> And finally, just to note that C and C++ are not 100% compatible anymore.
> Just to give an example:
> double* b = calloc(100, sizeof(*b)); is not valid C++.

Why would you ever do such a horrendously looking thing in C++? Yes, C is
not a proper subset of C++, that's a fact, but I never stated the opposite.

Yours,
Stefan
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