Prevent class inheritance in C++
c++, controls, inheritance
Solution
As of C++11, you can add the final keyword to your class, eg
class CBase final
{
...
The main reason I can see for wanting to do this (and the reason I came looking for this question) is to mark a class as non subclassable so you can safely use a non-virtual destructor and avoid a vtable altogether.
Problem
Recently one of my friend asked me how to prevent class inheritance in C++. He wanted the compilation to fail. I was thinking about it and found 3 answers. Not sure which is the best one. 1) Private Constructor(s) ``` class CBase { public: static CBase* CreateInstance() { CBase* b1 = new CBase(); return b1; } private: CBase() { } CBase(CBase3) { } CBase& operator=(CBase&) { } }; ``` 2) Using `CSealed` base class, private ctor & virtual inheritance ``` class CSealed { private: CSealed() { } friend class CBase; }; class CBase : virtual CSealed { public: CBase() { } }; ``` 3) Using a `CSealed` base class, protected ctor & virtual inheritance ``` class CSealed { protected: CSealed() { } }; class CBase : virtual CSealed { public: CBase() { } }; ``` All the above methods make sure that `CBase` class cannot be inherited further. My Question is: Which is the best method ? Any other methods available ? Method 2 & 3 will not work unless the `CSealed` class is inherited virutally. Why is that ? Does it have anything to do with vdisp ptr ?? PS: The above program was compiled in MS C++ compiler (Visual Studio). reference : http://www.codeguru.com/forum/archive/index.php/t-321146.html