学步园

//my_code.h
#include<iostream>
#include<string>
using namespace std;

class a{
public:
 int val;
 int val2;
};

//refback.h (auto gen)
template<typename T>
class refback{
public:
 template<typename Tret>
 static Tret T::* member(string){
  return 0;
 }
};
template<>
class refback<a>{
public:
 template<typename Tret>
 static Tret a::* member(string name){
  if(false){}
  else if(name=="val"){return &a::val;} //auto gen
  else if(name=="val2"){return &a::val2;} //auto gen
  else{return 0;}
 }
};

//main.cpp
int main(int argc, char** argv){
 a aa;
 aa.val=42;
 cout<<aa.*refback<a>::member<int>("val")<<endl;
 return 0;
}