#include <iostream>

//--------------------------------------------------------------------------------------------------------------------------------------
template <typename T>
struct CRTPcount
{
  private:
    static uint32_t mCreated;
    static uint32_t mCurrent;
  protected:
    CRTPcount()                   { ++mCreated; ++mCurrent; }
    CRTPcount( const CRTPcount& ) { ++mCreated; ++mCurrent; }
    virtual ~CRTPcount()          { --mCurrent; }
  public:
    static void usage_stats() { std::cout << "Class '" << typeid( T ).name() << "' | " << mCreated << " copies created | " << mCurrent << " copies currently alive" << std::endl; }
};

//Remembering to instantiate the static member variable
template <typename T> uint32_t CRTPcount<T>::mCreated( 0 );
template <typename T> uint32_t CRTPcount<T>::mCurrent( 0 );
//--------------------------------------------------------------------------------------------------------------------------------------

//--------------------------------------------------------------------------------------------------------------------------------------
class DerivedClassA : public CRTPcount< DerivedClassA > {};
class DerivedClassB : public CRTPcount< DerivedClassB > {};
// Can be used for an arbitrary number of classes of arbitrary nature
//--------------------------------------------------------------------------------------------------------------------------------------

//--------------------------------------------------------------------------------------------------------------------------------------
int main()
{
  // --------------------
  // Test default values
  DerivedClassA::usage_stats(); 
  // --------------------
  //Test default constructor
  DerivedClassA lA; 
  DerivedClassA::usage_stats();
  // --------------------
  // Test copy constructor
  DerivedClassA lA2( lA ) ; 
  DerivedClassA::usage_stats();
  // --------------------
  // Test destructor
  for( int i=0 ; i!=10 ; ++i ) DerivedClassB lB; //Scoped within the for-loop so they are created and immediately destroyed
  DerivedClassB::usage_stats();
  // -------------------- 
  return 0;
}
//--------------------------------------------------------------------------------------------------------------------------------------