Error C2662 Cannot

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Error C2662 Cannot Convert 'this' Pointer From

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Cannot Convert This Pointer From Const To &

million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Compile Error C2662 [duplicate] up vote 1 down vote favorite This question already has an answer here: c++ error const method C2662 cannot convert 'this' pointer from 'const Type' to 'Type &' 3 answers I'm trying to pass an object as a reference to a function that accepts the object as a const however the compiler is throwing: error C2662: 'const int DataPacket::GetData(void)': cannot convert 'this' pointer from 'const DataPacket' to 'DataPacket &' IntelliSense says: the object has type qualifiers that are not compatible with the member function object type is: const DataPacket I error c2662 cannot convert this pointer from const to conversion loses qualifiers made a test-cast of the code to demonstrate the issue: #include #include class DataPacket { int SomeVar; public: DataPacket(int InitialData) { SomeVar = InitialData; } const int GetData() { return SomeVar; } }; void ProcessPacket(const DataPacket& Packet) { std::cout << Packet.GetData() << std::endl; } int main() { std::function f_Callback; f_Callback = ProcessPacket; while (true) { f_Callback(DataPacket(10)); } } Basically I have a STD function which the user can set to use their own callback function. A lower level class creates objects of type DataPacket when new packets arrive. I then want to pass the object into the callback function as a constant reference so not to copy the entire object and restrict the user from changing the original object. What's going on here? How can I pass DataPacket into f_Callback as a const reference? c++ c++11 const pass-by-reference share|improve this question edited Jul 28 '14 at 4:11 user2864740 35.2k43779 asked Jul 18 '14 at 1:03 KKlouzal 13112 marked as duplicate by Praetorianc++ Users with the c++ badge can single-handedly close c++ questions as duplicates and reopen them as needed. Jul 18 '14 at 1:49 This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question. add a comm

Forum Visual C++ & C++ Programming Visual C++ Programming [RESOLVED] error C2662: cannot convert 'this' pointer from 'const Item' to 'Item &' If this is

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To start viewing messages, select the forum that you want to visit from the selection below. Results 1 to 11 of 11 Thread: [RESOLVED] error C2662: cannot convert 'this' pointer from 'const http://stackoverflow.com/questions/24815858/compile-error-c2662 Item' to 'Item &' Tweet Thread Tools Show Printable Version Email this Page… Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode March 6th, 2007,07:07 AM #1 Mybowlcut View Profile View Forum Posts Visit Homepage Senior Member Join Date Nov 2006 Location Australia Posts 1,569 [RESOLVED] error C2662: cannot convert 'this' pointer from 'const Item' to 'Item &' Hi guys! http://forums.codeguru.com/showthread.php?416873-RESOLVED-error-C2662-cannot-convert-this-pointer-from-const-Item-to-Item-amp The error: Code: error C2662: 'Item::GetName' : cannot convert 'this' pointer from 'const Item' to 'Item &' My class definition: Code: class Inventory { public: Inventory(vector ITEMLIST): itemList(ITEMLIST) {} inline void ListItems(); private: vector itemList; }; The class member function that the error is occurring in (error line in red): Code: inline void Inventory::ListItems() { if(itemList.empty()) cout << "\n\nYou have no items."; else { vector::const_iterator iter = itemList.begin(); for(iter; iter != itemList.end(); ++iter) { cout << "\n\n"; cout << iter->GetName(); } } } And the class (Item) member function that the iter is trying to access: Code: string GetName() { return name; } I can't get around this error.. it's beyond my knowledge I think. I've tried and I'm seeking helppppppp. If I'm missing anything out let me know! Good judgment is gained from experience. Experience is gained from bad judgment. Cosy Little Game | SDL | GM script | VLD | Syntax Hlt | Can you help me with my homework assignment? Reply With Quote March 6th, 2007,07:18 AM #2 0xC0000005 View Profile View Forum Posts Senior Member Join Date May 2002 Posts 1,435 Re: error C2662: cannot convert 'this' pointer from 'cons

return m_Color; } Flower &Flower::operator =(const Flower &f) { m_Color = f.GetColor(); return *this; } The complier tell me error C2662: 'Flower::GetColor' : cannot convert 'this' pointer from 'const Flower' to 'Flower &' I search about error http://www.cplusplus.com/forum/general/15391/ C2662, find that change the function GetColor with end of const: 1
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COLOR_ENUM Flower::GetColor(void) https://bytes.com/topic/c/answers/628845-error-c2662-cannot-convert-pointer const { return m_Color; } Then is complier stop telling me error. the question is why error C2662 is about convert 'this' ? I dont try convert 'this'; And funciton 'GetColor()' I must need 'const' even if I not change the class value? Oct 16, 2009 at 3:32am UTC helios (13227) I dont try convert error c2662 'this'Yes, you do. Non-const member functions can only take non-const this parameters. The compiler is not smart enough to look at your function and tell whether or not you're modifying the object. It needs the const there so that it can be sure that the object will not change. Consider that if you had a const int, you couldn't pass it to a function void (int &), because it error c2662 cannot requires that the parameter be non-const. This is exactly what's going on here. Last edited on Oct 16, 2009 at 3:33am UTC Oct 16, 2009 at 4:05am UTC player6 (40) Mmm....I don't understand this: Non-const member functions can only take non-const this parameters. Can you point out 'Non-const member functions' and 'non-const this parameters' in this funciton? Thank you~ Oct 16, 2009 at 4:08am UTC helios (13227) Non-const member function: COLOR_ENUM Flower::GetColor(void); Const member function: COLOR_ENUM Flower::GetColor(void) const; Oct 16, 2009 at 4:15am UTC player6 (40) But why 'this' is const? If it's const, when it become const? Oct 16, 2009 at 8:10am UTC Chewbob (95) It can be const when it does not modify any of its members. 1
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class A { int i; public: int f1() const { return i; } // legal because 'i' is not modified void f2() const { ++i; } // error because it modifies 'i' }; Oct 16, 2009 at 9:19am UTC player6 (40) 'Flower::GetColor' : cannot convert 'this' pointer from 'const Flower' to 'Flower &' Ok, I know, in the error information 'this' is 'f' in m_Color = f.GetColor(); rather than 'this' in return *this; I think I mistake 'this'. Thanks Topic archived. No new replies allowed. C

your question and get tips & solutions from a community of 418,505 IT Pros & Developers. It's quick & easy. error C2662 cannot convert this pointer.. P: 9 mishink7 i am getting this error error C2662: 'std::vector<_Ty>::push_back' : cannot convert 'this' pointer from 'const std::vector<_Ty>' to 'std::vector<_Ty> &' with [ _Ty=std::string ] and [ _Ty=std::string ] and [ _Ty=std::string ] this is my code inside the class customer void customer::add_movie(string move) const { int flag1=0; for (unsigned int i=0; i movies. ive tried doing different things, but i cant fix it, can anyone help please? Apr 6 '07 #1 Post Reply Share this Question 3 Replies P: 9 mishink7 bumpssssssssssss Apr 6 '07 #2 reply Expert Mod 5K+ P: 8,916 Banfa bumpssssssssssss Only waiting an hour before bumping is really not waiting long enough. The forum experts are not all in the same time zone as you. You should leave a post at least 24 hours before bumping. Apr 6 '07 #3 reply Expert Mod 5K+ P: 8,916 Banfa error C2662: 'std::vector<_Ty>::push_back' : cannot convert 'this' pointer from 'const std::vector<_Ty>' to 'std::vector<_Ty> &' with [ _Ty=std::string ] and [ _Ty=std::string ] and [ _Ty=std::string ] Read the error, the is a type mismatch between 'const std::vector<_Ty>' to 'std::vector<_Ty> &' where_ty=std:string (or string). Substituting there is a type mismatch between 'const std::vector' to 'std::vector &', you can not convert between a const object an a non-const reference to an object. Now look at your function Expand|Select|Wrap|Line Numbers voidcustomer::add_movie(stringmove)const { intflag1=0; for(unsignedinti=0;i movies. See any const qualifiers? Yes on the function, that const is telling the compiler that this function does not alter any member variables and that all member va