c++ polymorphism of operator overloading

Question

How can I make pure virtual function a operator+(); function. wheh ı do like this in base class int operator+()=0; compiler gives error . in derive class operator+() funct

Answer 1

 #include 
using namespace std;
class ana {
    protected :
    int x;
    public :


virtual int operator+()=0;
virtual void operator=(ana&)=0;
    };

class baba:public ana{
    public:
    baba(int k){x=k;}
    int   operator+(baba &ali){
        int k;
        k=x+ali.x;
        return k;
    }
   void operator=(baba &ali){
       x=ali.x;
       }

};


int main(){
baba k(4);

return 0;
}what is wrong here?