I have a struct template A<x> and B<x>, an operator overload for A<x>+int and a conversion from B<x> to A<x>. I want B<x> to be converted to A<x> when adding with int, so I used friend function declaration.
#include <iostream>
template<int x>
struct A{
int a;
};
template<int x>
struct B{
int b=3;
operator A<x>(){
return {b+10};
}
friend int operator+(A<x> a, int b);
};
template<int x>
int operator+(A<x> a, int b){
return a.a+b;
}
int main(){
std::cout<<(A<12>{9}+10)<<std::endl; // This works fine
std::cout<<(B<12>{9}+10)<<std::endl; // Error
return 0;
}
Now the linker complains that 'operator+(A<12>, int)' is not defined. Could somebody tell me what's wrong with this?
