A programming question
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Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding... -
Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding... -
The first time I read about them (years ago), they made no sense to me. The last reading I did made them seem like
protectedinheritance madepublicmembersprotected, andprivateinheritance madepublicmembersprivatein the derived class. I can see this maybe being useful in some situations, but am curious as to where that would be the case. -
The first time I read about them (years ago), they made no sense to me. The last reading I did made them seem like
protectedinheritance madepublicmembersprotected, andprivateinheritance madepublicmembersprivatein the derived class. I can see this maybe being useful in some situations, but am curious as to where that would be the case. -
Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding...I'm not a regular C++ dev but I've never had a reason to use them so far. I've also never seen a good example of why they're useful that can't be solved in another way (e.g. composition). Whether you value it or not is up to you and the situation, but it's worth mentioning that private and protected inheritance breaks the Liskov Substitution Principle, and private inheritance breaks polymorphism in the inheritance hierarchy. Honestly though, I'd love to see an example of either being useful.
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Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding...You maybe used composition to define 'has-a' relations... that's the way C# preferred, so no private inheritance there...
"The only place where Success comes before Work is in the dictionary." Vidal Sassoon, 1928 - 2012
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Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding...Well, If you ever get to work at a company with thousands of developers (or as a program manager) you'll quickly understand the value. They are a very useful tool for controlling the application binary interface[^]. Let's say that you create an awesome library called DoSomethingAwesome.lib and everybody at your company wants to use DoSomethingAwesome. They take your lib as a dependency and quickly integrate it into dozens of projects. They derive classes from your headers and extend them and now it's DoSomethingMoreAwesome. Then your team changes some of the internals and DoSomethingAwesome is no longer compatible with DoSomethingMoreAwesome. In fact now dozens of other teams at the company are having to re-write parts of their code to accommodate for the changes in your lib. Paying software engineers is expensive and now this change has cost the company thousands of dollars. The concept of protected and private inheritance is a useful tool that allows the library development team to control the public interfaces and keep a stable ABI. It's just a tool in the toolbox. Best Wishes, -David Delaune
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The first time I read about them (years ago), they made no sense to me. The last reading I did made them seem like
protectedinheritance madepublicmembersprotected, andprivateinheritance madepublicmembersprivatein the derived class. I can see this maybe being useful in some situations, but am curious as to where that would be the case.All members of the base class get restricted to the inheritance type. So both public and protected members of the base class are now private in the derived class if using private inheritance. So any users of that derived class don't "see" the inheritance. As I said in my other post, I've never seen a good example of why this would be needed though :confused: EDIT: Two words for clarity. Also private base class members are still not visible to the derived class iirc.
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Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding...You use inheritance when a derived type must implement the functionality of the base type. * Public inheritance is used when the public functionality of the base type may be used by anyone. * Protected inheritance is used when the public functionality of the base type may be used only by further-derived types. * Private inheritance is used when the public functionality of the base type may not be used by further-derived types. An example for private (or protected) inheritance might be a wrapper for the HANDLE object in Windows. A HANDLE wrapper may be constructed directly so its constructor must be public, but inside a File object you probably want only the File object (or its derived types) to be able to access the HANDLE.
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows. -- 6079 Smith W.
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Well, If you ever get to work at a company with thousands of developers (or as a program manager) you'll quickly understand the value. They are a very useful tool for controlling the application binary interface[^]. Let's say that you create an awesome library called DoSomethingAwesome.lib and everybody at your company wants to use DoSomethingAwesome. They take your lib as a dependency and quickly integrate it into dozens of projects. They derive classes from your headers and extend them and now it's DoSomethingMoreAwesome. Then your team changes some of the internals and DoSomethingAwesome is no longer compatible with DoSomethingMoreAwesome. In fact now dozens of other teams at the company are having to re-write parts of their code to accommodate for the changes in your lib. Paying software engineers is expensive and now this change has cost the company thousands of dollars. The concept of protected and private inheritance is a useful tool that allows the library development team to control the public interfaces and keep a stable ABI. It's just a tool in the toolbox. Best Wishes, -David Delaune
Thank you Very Much for this explanation! As I said before, I am in awe of your talents, and this is helpful for my understanding!
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Thank you Very Much for this explanation! As I said before, I am in awe of your talents, and this is helpful for my understanding!
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Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding...Yes, they come very handy to define the degree of derivation freedom you want to let users for your interface elements. Why the question ?
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Yes, they come very handy to define the degree of derivation freedom you want to let users for your interface elements. Why the question ?
Rage wrote:
Why the question ?
Because I have never seen good examples for
publicandprivatederivation. -
Well, I dunno man, when I read this headline the other day I was almost certain they were referring to software engineers. America is facing a monkey shortage[^] Best Wishes, -🐵🍌
The abbreviation is overused, but lol!
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Rage wrote:
Why the question ?
Because I have never seen good examples for
publicandprivatederivation.Oh. I was hoping for a more crunchy story with secret services and hacking passwords.
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Oh. I was hoping for a more crunchy story with secret services and hacking passwords.
Sorry to disappoint you, but I am a mere mortal programmer. :laugh: I don't have time to brute force passwords and such...
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Sorry to disappoint you, but I am a mere mortal programmer. :laugh: I don't have time to brute force passwords and such...
That's because you do not use private and protected inheritance... :laugh:
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That's because you do not use private and protected inheritance... :laugh:
+10! Made me laugh!
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+10! Made me laugh!
(And also made me a bit sad, that we are overwriting the lives of other species to supposedly improve our own.)
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Disregarding the flagrant violation of protocol, and the total disregard of the red text at the top of the forum, those of you who have programmed in C++, have you ever used
protectedandprivateinheritance? I've never had a use for it, but have been extremely curious about when they are handy. They are not in C# (from what I've read), but maybe I've overlooked something, and they are useful in ways I don't know? Your thoughts and experiences, to expand an undeveloped understanding...I have used private inheritance. The base class public access members are still public access in the derived class. Therefore the derived class still can call the base class functions and access its public data. But the user who instantiates the derived class, cannot access the public member of the base class, hence private inheritance. Public inheritance is a "is-a" relationship. Private inheritance is a "implemented-in-terms-of" relationship. A useful example, is I like .NET string class and like a C++ string class with the same C# methods but I do not want to reimplement from scratch, so I derived from
std::wstringwith private inheritance to make use of its functionality, so that user of my string class cannot access the base class'sstd::wstringto avoid the confusion.class MyString : private std::wstring
{
};There is an excellent blog about this topic: [C++ Tutorial: Private Inheritance - 2020](https://www.bogotobogo.com/cplusplus/private\_inheritance.php)
