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Cannot Be Declared Both Virtual And Static


Why is this C++ code faster than my hand-written assembly for testing the Collatz conjecture? But what exactly is possible, let's narrow down. isApproved() must be a simple function of a string. Solutions? have a peek here

You can check it your class has at least one virtual function then class size will increase by 4 (size of pointer) OM Perfect Answer thanks Durga " static function doesn't What did John Templeton mean when he said that the four most dangerous words in investing are: ‘this time it’s different'? isApproved() should not be implemented in the base Document class. 2. share|improve this answer edited Aug 22 '12 at 16:44 answered Nov 30 '09 at 15:39 Nate C-K 4,37511531 That's going to cost me performance - unless the compiler can http://stackoverflow.com/questions/7227236/can-we-have-a-virtual-static-method-c

Virtual Static C#

thanks , Ron c++ static virtual share|improve this question asked Aug 29 '11 at 7:22 Ron_s 5341618 marked as duplicate by Charles Bailey, ChrisWue, Matthieu M., Bo Persson, Nicol Bolas Aug I'm still thinking about a way to fix that. Hi, I know that it is illegal in C++ to have a static pure virtual method, but it seems something like this would be useful when the following 2 conditions hold: It won't work if we need to call non-public functions though.

If you make isApproved a public function, then you can usea template function like this: template void processDocument(documnetAuthor){ if (T::isApproved(documentAuthor)) T::SomeNonVirtualF; else T::SomeOtherNonVirtualF;} and call it like this processDocument(documentAuthor); simulating "static pure virtual" methods P: n/a cppaddict Hi, I know that it is illegal in C++ to have a static pure virtual method, but it seems something like this would Derived aDerived; // Declare two pointers, one of type Derived * and the other // of type Base *, and initialize them to point to aDerived. C++ Overload Static Method Pointers to class members are special in semantics and syntax.

One could imagine C++ allowing calling statics from an instance (e.g., Foo foo; ... Both the override method and the virtual method must have the same access level modifier.You cannot use the new, static, or virtual modifiers to modify an override method.An overriding property declaration So we have the following: 1. http://stackoverflow.com/questions/9863007/can-we-have-a-static-virtual-functions-if-not-then-why Is it possible to bleed brakes without using floor jack?

One point, the introduction of the strategy pattern doesn't necessarily mean the elimination of the virtual function in the document class : virtual bool isApproved( ){ return _approver->isApproved( authorName) ;}; Here Why Virtual Function Cannot Be Friend isApproved() must be implemented in any derived concrete class. 3. Please use code.geeksforgeeks.org, generate link and share the link here. [V] The static member function can't access non-static data members/functions of a class. They just happen to be invoked by ClassName::member, and adhere to the class access specifiers.

C++ Override Static Method

Dev centers Windows Office Visual Studio Microsoft Azure More... Homepage Account *pAccount = pChecking; // Call Account::PrintBalance pAccount->Account::PrintBalance(); // Explicit qualification. Virtual Static C# Shekhu Doesn't look very obvious to me. Why Static Member Function Cannot Be Const Singular cohomology and birational equivalence Depalindromize this string!

I changed one method signature and broke 25,000 other classes. navigate here struct ObjectVisitor; struct Object { struct TypeInformation; static TypeInformation GetTypeInformation(); virtual void accept(ObjectVisitor& v); }; struct SomeObject : public Object { static TypeInformation GetTypeInformation(); virtual void accept(ObjectVisitor& v) const; }; struct Not the answer you're looking for? You do have to instantiate the class for each type you want to check explicitly. C++ Static Abstract Method

Indeed, to give it context, I could have it operate on _documentAuthor directly instead of passing that in as an argument. Thanks, cpp Jul 22 '05 #1 Post Reply Share this Question 12 Replies P: n/a Sharad Kala "cppaddict" wrote in message news:ck********************************@4ax.com... This is where pure virtual comes in. 2. http://electrictricycle.net/cannot-be/cannot-be-declared-in-this-scope-because-it-would-give.html iptables not dropping by IP and port?

This does obviously only work, if the base class knows how to access the static member function. C++ Virtual Static Variable You know that for every one of your Derived classes, the method never uses or alters member data. For example, I had a family of MouseTool classes for the State pattern and I started having each one have a static function returning the keyboard modifier that went with it;

virtual functions in a class needs the this pointer, and is very coupled to the class, hence they can't be static.

asked 6 years ago viewed 36791 times active 2 years ago Linked 101 C++ static virtual members? 26 In C++, is it safe/portable to use static member function pointer for C So - that's not a reason virtual static members are impossible. –einpoklum Feb 3 at 19:49 add a comment| up vote 6 down vote Well , quite a late answer but Thus it should be static. Why Static Member Function Cannot Have This Pointer All three compile and run without warnings or errors. –Rob Kennedy Apr 28 '10 at 4:54 1 It might work on most compilers now, but i think it should at

The things that doesn't work with structure is only abstract and virtual. It just does not make sense, what instance are they not going to mutate? –David Rodríguez - dribeas Dec 1 '09 at 8:48 This is mostly just code duplication. When you build a "T" object, the function pointers in this table are assigned to the addresses of 1st ancestor providing that API. this contact form Think of a getInstance() function for example for making singleton.

Player claims their wizard character knows everything (from books). I think the Visitor Pattern can give you what you want.