// test.cpp
  include <iostream>
  include <exception>
  using namespace std;
  
  class base
  {
  public:
    base() {}
    virtual ~base() {}
  };
  
  class derived : public base {};
  
  int main(int argc, char** argv)
  {
    base* b = new derived();
    derived* d = dynamic_cast<derived*>(b); // use RTTI
    if (d == NULL) {
      throw exception(); // use exceptions
    }
    return (0);
  }