c++ - undefined reference to vtable after the creation of a class object -

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• c++ undefined reference vtable , inheritance 3 answers

i have following 2 classes:

class grill { public:   virtual ~grill();   virtual std::string get_model() const{return _model;};   virtual void set_price(float p){_price=p;};   virtual float get_price() const {return _price;};   virtual grill* clone()=0; protected:   grill(std::string m,float p):_model(m),_price(p){};   grill(const grill& obj)=default;   grill(grill&& obj)=default;   std::string _model;   float _price; private:   grill& operator=(const grill& obj)=delete; };   class grill_charcoal final : public grill {  public:   grill_charcoal(std::string m,float p):grill(m,p){};   ~grill_charcoal(){};   grill_charcoal* clone() override{return new grill_charcoal(*this);};  protected:   grill_charcoal(const grill_charcoal& obj)=default;   grill_charcoal(grill_charcoal&& obj)=default;  private:   grill_charcoal& operator=(const grill_charcoal& obj)=delete; }; 

in main want create vector stores pointers grill objects. create vector<grill*>. problem when create object. main is:

int main() {    using namespace std;     vector<grill*> grill;     grill_charcoal* gp=new grill_charcoal("adsaas",2312); //error    //grill.push_back(new grill_charcoal("sdsaa",22)); //error well, not compiled     return 0; } 

the g++ shows following errors:

in function `grill::grill(std::string, float)': program6.cc:(.text._zn5grillc2essf[_zn5grillc5essf]+0x1c): undefined reference `vtable grill' /tmp/ccjlugr9.o: in function `grill_charcoal::~grill_charcoal()': program6.cc:(.text._zn14grill_charcoald2ev[_zn14grill_charcoald5ev]+0x1f): undefined reference `grill::~grill()' /tmp/ccjlugr9.o: in function `grill::grill(grill const&)': program6.cc:(.text._zn5grillc2erks_[_zn5grillc5erks_]+0x17): undefined reference `vtable grill' /tmp/ccjlugr9.o:(.rodata._zti14grill_charcoal[_zti14grill_charcoal]+0x10): undefined reference `typeinfo grill' collect2: error: ld returned 1 exit status 

any explanation why happen?

the error message spells out ... declared ~grill() never defined it.