How C++ class multiple inherit and namespace to ObjFPC?

[TYDQ]

The sample C++ code is:

Code: C  [Select][+][-]

1. #pragma once
2.  
3. #include <iostream>
4. #include <string>
5.  
6. using namespace std;
7.  
8. class Furniture
9. {
10. public:
11.     Furniture(void) : m_weight(0){}
12.     Furniture(double weight) : m_weight(weight){}
13.     ~Furniture(void){}
14.  
15.     double GetWeight() const { return m_weight; }
16.     void SetWeight(double val) { m_weight = val; }
17.  
18. private:
19.     double m_weight;
20.  
21. };
22.  
23. class Bed : public Furniture
24. {
25. public:
26.     Bed() : Furniture(), m_second(0) {}
27.     Bed(double weight, int second) : Furniture(weight), m_second(second){}
28.  
29.     void Sleep(int second)
30.     {
31.         m_second = second;
32.     }
33.  
34.  
35. private:
36.     int m_second;
37.  
38. };
39.  
40. class Sofa : public Furniture
41. {
42. public:
43.     Sofa() : Furniture() {}
44.     Sofa(double weight) : Furniture(weight){}
45.  
46.     void WatchTV(string  programme)
47.     {
48.     }
49. };
50.  
51. class SleepSofa : public Bed, public Sofa
52. {
53. public:
54.     SleepSofa() : Bed(), Sofa() {}
55.     SleepSofa(double weight, int second) : Bed(weight, second), Sofa(weight) {}
56.  
57.     void FoldOut()
58.     {
59.         Sleep(360);
60.     }
61. };

How to translate these C++ code to Object Free Pascal?(The namespace can be self-defined,though.)

[Thaddy]

Object Pascal does not support multiple inheritance.
(even Bjarne Stroustrup, the creator of C++, thought that was a really bad idea with hindsight)
BUT...You can mimic it with interfaces.

Also, It is very rare in C++ circles that it is used, let alone used correctly.
It is the single most unloved "feature" of C++.

Using interfaces - in this case COM or CORBA does not matter - leads to easier to understand and maintain code. (Bjarne said so)

I wasted half of my life writing C and C++ code and only 25% writing Pascal and never needed that.
https://stroustrup.com/bs_faq2.html
https://www.usenix.org/legacy/publications/compsystems/1989/fall_stroustrup.pdf

So idiots that claim to the contrary can shut up immediately.
 

If Bjarne says no, and you still want to use it, you are an idiot.
Note I documented it undeniably so don't even bother to reason otherwise.

[TYDQ]

Object Pascal does not support multiple inheritance.
(even Bjarne Stroustrup, the creator of C++, thought that was a really bad idea with hindsight)
BUT...You can mimic it with interfaces.

Also, It is very rare in C++ circles that it is used, let alone used correctly.
It is the single most unloved "feature" of C++.

Using interfaces - in this case COM or CORBA does not matter - leads to easier to understand and maintain code. (Bjarne said so)

I wasted half of my life writing C and C++ code and only 25% writing Pascal and never needed that.
https://stroustrup.com/bs_faq2.html
https://www.usenix.org/legacy/publications/compsystems/1989/fall_stroustrup.pdf

So idiots that claim to the contrary can shut up immediately.
 

If Bjarne says no, and you still want to use it, you are an idiot.
Note I documented it undeniably so don't even bother to reason otherwise.

OK,C++ is more complex than I can understand.Thanks to your advice.

[Thaddy]

C++ is not complex, but multiple inheritance is - or can be - complex. And stupid.
( like with in Pascal)

[alpine]

So idiots that claim to the contrary can shut up immediately.
 

If Bjarne says no, and you still want to use it, you are an idiot.
Note I documented it undeniably so don't even bother to reason otherwise.

I have used it sometimes by inheriting (multiple) pure virtual classes in purpose to mimic the D/FPC interfaces. 
That way they can be useful, I think.

[Thaddy]

I think.

Are you sure?

[alpine]

I think.

Are you sure?

Quite sure. Pure virtual classes inherited as interfaces.

Using interfaces - in this case COM or CORBA does not matter - leads to easier to understand and maintain code. (Bjarne said so)

[Thaddy]

I told you so:

]BUT...You can mimic it with interfaces.

Good luck.

[alpine]

I told you so:

]BUT...You can mimic it with interfaces.

Good luck.

No, it is the other way around - using C++ MI with pure virtual classes in place of FPC interfaces. --Bjarne said so.

[Thaddy]

NO
Good luck,

[PascalDragon]

NO
Good luck,

Yes, it is. C++ classes that only have virtual, abstract methods are essentially equivalent to CORBA interfaces (minus the ID string). Also C++ uses classes with virtual, abstract methods to represent COM interfaces (inheriting from a IUnknown base class).
C++ itself doesn't have interfaces as such.

[VisualLab]

Also, It is very rare in C++ circles that it is used, let alone used correctly.
It is the single most unloved "feature" of C++.

But not as rare as you suggest. This feature is used in the BeOS and Haiku OS APIs. Besides, these OSs are written in C++ (apart from parts of the kernel, which were written in C). And while I don't like C++ (and STL has particularly ugly code), the BeOS API was quite nice (for C++).

[Thaddy]

Well, when I was learning for my Borland trainer certificate we struggled to come up with a single example.

[TYDQ]

C++ is not complex, but multiple inheritance is - or can be - complex. And stupid.
( like with in Pascal)

However,C++ grow more complex as many features announced in C++23 and later standard published.I think long history open-source C/C++ projects like binutils will use C++11 standard as the main standard to write the code.
So in your view what the C++ standard newest version of open-source C/C++ projects like binutils will use(I am writing my C2pas,so I want to know what feature in C++ will be used in these projects)?

[PascalDragon]

I think long history open-source C/C++ projects like binutils will use C++11 standard as the main standard to write the code.

GNU Binutils is written in C, not C++ and they won't simply change the language, so if at most they'll change to newer versions of the C standard. But even then the developers will very likely restrain themselves, because GNU Binutils are also available for older systems that don't support newer C standards.