Compile time polymorphism: avoiding the short commings of virtual functions with the curiously recursive template pattern.

CRTP.cc

#include <iostream>

class Base {
 public:
  Base() { ; }
  ~Base() { ; }
  
};

template <typename Derived>
class Base_CRTP : public Base {
public:  
  auto get_member() { return static_cast<Derived*>(this)->member; }
  
};


class ChildA : public Base_CRTP<ChildA> {
  public:
  float member = 3.14159;
};


class ChildB : public Base_CRTP<ChildB> {
  public:
  int member = 42;
};

int main() {
  ChildA a_child;
  ChildB b_child;
  
  std::cout << a_child.get_member() << " " << b_child.get_member() << std::endl;
  
  return 0;
};