If you think C++ is not overly complicated, just what is a protected abstract virtual base pure virtual private destructor and when was the last time you needed one?
I know the original quote was meant as a complaint about C++, but it’s always seemed to me to be more about how people were teaching C++ in the ‘90s.
What about the zinger, “if you think English is not overly complex, just what is a loud old fast tall red car, and when was the last time you needed one?” No language I’m familiar with limits the number of adjectives you can use for a single noun. That doesn’t mean you generally should string several adjectives together; usually you’re fine just saying “car,” but sometimes you need the ability to be specific. English is a complicated language, but limiting how many adjectives can apply to a particular noun would make it much worse in my opinion.
As for the original question, a pure virtual function is a function that must be implemented in a derived class, while a private function is a function that can’t be accessed outside of the class, not even from derived classes. A destructor is a function used to clean up when an object goes out of scope; I don’t think anything about the destructor is important in this case, it just happens to be a convenient member function to use.
The combination would make it impossible to instantiate objects of the class (because of the pure virtual function) or objects of classes that inherit from it (because the pure virtual function can’t be accessed, let alone implemented, from a derived class). That rules out much of what you’d want to do with a class. You’re left with static data and functions, and nested types. Overall, the best I can tell, you would use that to make the class imitate a namespace. But for the last twenty years, you don’t have to imitate namespaces: C++ has them.
You might still find somebody trying to avoid using actual namespaces because of a vague fear of argument dependent lookup, but to be honest, I’ve never seen argument dependent lookup call the wrong function. Some programmers oppose it in principle, but in practice it doesn’t seem to cause much trouble.
If you think C is not overly complicated, just what is a static const __declspec((dllimport)) __restrict volatile unsigned long long int* and when was the last time you needed one?
Considering that half of that is not standard C code, and the other is just a standard way of declaring a pointer that doesn’t differ much in any other typed language, i don’t think you’re making a point here.
I would agree, if you take out the __declspec((dllimport) then it's just a 'static const restrict volatile long long int * ', which has lots of qualifications but isn't really much more then just a pointer to a `long long`. The qualifiers make it a bit harder to reason about, but that's also why people rarely use `restrict` and `volatile` in the first place.
I could be wrong but I think the above poster hasn't actually written tons of C, or else they would have picked a much more complicated example. If you throw a bunch of arrays, pointers, and function pointers in it quickly gets out of hand, like this:
int (* const(*foo)(int (*)(int, int))[5])(void);
That thing defines 'foo', which is a pointer to a function who's first argument is a pointer to a function return a int and taking two ints as arguments, and returns a pointer to an array of 5 const function pointers which take no arguments and return an int.
Thankfully, you rarely run into something like that in the wild. And if you `typedef` the function pointers (Which is a pretty common now) it becomes tons easier to read.
> That thing defines 'foo', which is a pointer to a function who's first argument is a pointer to a function return a int and taking two ints as arguments, and returns a pointer to an array of 5 const function pointers which take no arguments and return an int.
I find this much easier to understand than something with different keywords and qualifiers. Function pointers follow some simple rules to read, but can you be sure of what `volatile` implies ?
> I find this much easier to understand than something with different keywords and qualifiers. Function pointers follow some simple rules to read, but can you be sure of what `volatile` implies ?
Hmm, I suppose we just disagree then, which is fine. Things like `restrict` and `volatile` don't really bother me because:
1. The spots where people actually need to use them are very rare (`restrict` does have uses, but almost nobody uses it commonly. `volatile` has pretty much no correct uses outside of accessing registers in low-level code).
2. It's still just a pointer to a long long. I would need to look-up what __declspec((dllimport)) does, and I'd be highly suspicious of the use of `restrict` and `volatile` if it was not explained, but I still generally know what it is and how it can be used. Whereas with the example I gave, without staring for a long time or throwing it into a parser I can hardly tell what the type even is, let alone wrap my head around how it will be used.
>`volatile` has pretty much no correct uses outside of accessing registers in low-level code
Sorry, but what are you guys on about? You use "volatile" if you don't want the compiler to produce code that caches a variable. You use it all the time in embedded systems, or when writing multi-threaded code, etc. The usage of "volatile" is very clear, and should be well understood. "restrict" isn't used much because it's a c99 standard first of all, and second of all, it's like "inline"; it might make a difference, might not, and not a lot of people are in a situation where they have to shave off cycles.
Well... the declaration you cited resolves down to a pointer to a wide integer. Part of C's simplicity is its small number of keywords, many of which have become way too overloaded as architectures have grown more advanced. The keywords were decided in the 1970s, when address spaces were 16 bits at the most. The ability to create type aliases with `typedef` has added to this apparent complexity, and this has been abused by compiler and OS vendors for decades.
None of it makes the language inherently any more complex, any more than representing machine instructions by long strings of binary makes _them_ any more complex.
What about the zinger, “if you think English is not overly complex, just what is a loud old fast tall red car, and when was the last time you needed one?” No language I’m familiar with limits the number of adjectives you can use for a single noun. That doesn’t mean you generally should string several adjectives together; usually you’re fine just saying “car,” but sometimes you need the ability to be specific. English is a complicated language, but limiting how many adjectives can apply to a particular noun would make it much worse in my opinion.
As for the original question, a pure virtual function is a function that must be implemented in a derived class, while a private function is a function that can’t be accessed outside of the class, not even from derived classes. A destructor is a function used to clean up when an object goes out of scope; I don’t think anything about the destructor is important in this case, it just happens to be a convenient member function to use.
The combination would make it impossible to instantiate objects of the class (because of the pure virtual function) or objects of classes that inherit from it (because the pure virtual function can’t be accessed, let alone implemented, from a derived class). That rules out much of what you’d want to do with a class. You’re left with static data and functions, and nested types. Overall, the best I can tell, you would use that to make the class imitate a namespace. But for the last twenty years, you don’t have to imitate namespaces: C++ has them.
You might still find somebody trying to avoid using actual namespaces because of a vague fear of argument dependent lookup, but to be honest, I’ve never seen argument dependent lookup call the wrong function. Some programmers oppose it in principle, but in practice it doesn’t seem to cause much trouble.