All points you made are wrong
So, you had failed a simple job interview about C++ based on wrong answers regarding constructors, wow
I did not define a virtual destructor as it is irrelevant for this example.
Good, now you know the member variables of B are not initialized at all, dare to try a new answer
My bet: your answer will be wrong again
Do you remember a language name? I'm looking for an interpreted MI capable language to port to iOS and use as scripting language for an App.
Any idea?
Perhaps read a book about the Taligent Frameworks?
When do you use (single) inheritance? When you "extend" a class or when you "specialize" a class? Whenever you want to extend a class in C++ (lets name it B) you should not inherit from it but craft a new class (lets name it N), worst case via a mixin template construct, and compose the desired class by multiple inheritance so that D is specializing B and N.
That way you can reuse N without being dependent or messing up D or B.
The simplified single inheritance and interface model caters for all practical examples, and *vastly* simplifies the internal workings. (X)
No, it does not. As you have to program the implementation of everything you "inherit interface wise" multiple times everywhere where you "implement" that interface.
If you want to use simple delegation (via IDE code generation etc.) the delegatee loses the original this pointer
How large is a pointer to a member variable?
That is a stupid question. Yes, I know there are no stupid questions, only stupid answers. However asking questions that don't belong to the context: is stupid.
Answer to your question: implementation dependent. What exactly do you mean with a pointer to a member anyway? A true C++ member pointer? Like &classname::member? Usually as big as any pointer on the given platform. But can be optimized as small as a byte, however I'm not aware of any compiler that does that.
If you mean &object.member, a safe bet is: the size equals the typical pointer size on the given platform.
I did not argue about "shared_ptr", that was someone else.
The article you linked is bogus. I stopped reading after this: Ownership of resources is a central part of software engineering.
That is plain wrong. The idea of "ownership" was introduced with C++
Example:
class Person {
Person *spouse;
}
Who owns whom, when to delete the spouse? Obviously the idea that one person owns the other one makes no sense in terms of C++
The answer is, if you use an uninitialized variable, the results are undefined.
Your answer is wrong.
I suggest to read a book about C++ and the mess about constructors.
If you ask politely I explain you what is going to happen depending on where you use either B or D
So you never tried the -auto-fix option?
Shame on you!
C++ is harder than other languages.
E.g. "a constructor for a class is auto generated by the compiler when needed"
Under what circumstances does this rule apply?
Oh, and what are the pitfalls?
E.g.
class B {
int i;
float f;
}
class D : public B {
int s;
public:
D() {
s = 5;
}
}
B b;
D d;
What value has b.i?
What value has d.i?
Hint: consider B and D to be in different compilation units.
My bet: your answer is wrong.
Wow: that above was a super simple example about problems in C++ that make C++ a very hard language
Actually it goes like this:
C: You shoot yourself into the foot.
C++: You shoot yourself into the foot, and have blown of your whole leg.
Yes, it should.
But actually C++ is a beast of a language which no one so far quickly mastered.
All we have now in C++, like STL, boost etc. is stuff that was envisioned by people who minimum had 10 years language experience before they even came to the idea to (ab)use language features like that.
When I read the first time about the concepts of the STL (that was round 1993, and it was not even called STL then) I was shocked about its simplicity and that I was so dumb that I never came to that idea myself. Basically the only "genious" I had at that time was that I had invented "traits" myself
In the field I work in, we aren't allowed to use RAII; we compile with it turned off.
You are mistaken.
You can not turn of RAII. It is only a constructor call and a destructor call.
Properties are easy achieved in C++ by using so called "property templates" where you wrap attributes into such a template and overwrite operator = for assignment and the cast operator for reading
Perhaps you should catch up and buy one of the 20 year old C++ books
Nothing beats C++ in multiple inheritance (which Java does not have and Groovy/Scala only mimic half arsed) and in templates, which Java/Groovy does not have either. Not sure about Scala, originally they wanted real templates, but no idea if they scaled down to generics, too.
For non-ducks, the most important things to know about C++ aren't list in the summery: RAII and shared_ptr<T>
That is not really correct. As soon as you know about ctors and dtors you know about RAII, no special "point in the list" needed.
Because it is not a scale but a method of teaching music/notes.
And as to 4 above, that stands on its own. Again, OCO2 shows how much China emits, which is far far more than is generally admitted since Chinese leaders are lying.
How stupid are you?
Who cares what China is saying?
We know how much CO2 they produce by simply counting their oil, coal production, cars and power plants.
Man, what a no brainer.
No idea why you try to use propaganda links like the first one, which is an _american_
China's emissions from 1850 on, exceed America's total.
Very unlikely and no one can figure which is the case as we have no data bout that, neither from China nor from the USA, so it is completely brain dead to argue about that.
We are each entitled to our own opinion, but no one is entitled to his own facts. -- Patrick Moynihan
