템플릿 구현 시 value type의 리스트를 만들었을 때 소멸자 문제

#include <iostream>
 
#if __cplusplus >= 201103L
#include <type_traits>
#else
// en.cppreference.com/w/cpp/types/remove_cv
template< class T > struct remove_const          { typedef T type; };
template< class T > struct remove_const<const T> { typedef T type; };
 
template< class T > struct remove_volatile             { typedef T type; };
template< class T > struct remove_volatile<volatile T> { typedef T type; };
 
template< class T >
struct remove_cv {
    typedef typename remove_volatile<typename remove_const<T>::type>::type type;
};
 
template< bool v > struct bool_constant { enum {value = v}; };
struct true_type  : public bool_constant<true> {};
struct false_type : public bool_constant<false> {};
 
// en.cppreference.com/w/cpp/types/is_pointer
template< class T > struct is_pointer_helper     : public false_type {};
template< class T > struct is_pointer_helper<T*> : public true_type {};
template< class T > struct is_pointer : public is_pointer_helper<typename remove_cv<T>::type> {};
#endif
 
using namespace std;
 
template< typename T, bool is_pointer >
class sample_base;
 
template< typename T >
class sample_base<T, false>{
protected:
	T field;
public:
	sample_base(T init):field(init){
		return;
	}
	~sample_base(void){
		cout << "This object has no pointer." << endl;
		return;
	}
};
 
template< typename T >
class sample_base<T, true>{
protected:
	T field;
public:
	sample_base(T init):field(init){
		return;
	}
	~sample_base(void){
		cout << "This object has a pointer." << endl;
		delete field;
		return;
	}
};
 
template< typename T >
class sample : protected sample_base<T, is_pointer<T>::value>{
public:
	typedef sample_base<T, is_pointer<T>::value> base;
	sample(T init):base(init){
		return;
	}
	~sample(void){
		return;
	}
 
	// other member functions...
};
 
int main(void){
#ifdef __cplusplus
	cout << "__cplusplus: " << __cplusplus << endl;
#else
	cout << "no __cplusplus defined." << endl;
#endif
	{
		cout << "sample<int>:" << endl;
		sample<int> sample_int(0);
	}
	{
		cout << "sample<int *>:" << endl;
		sample<int *> sample_int_p(new int(0));
	}
	return 0;
}