traits

using namespace std;


template <class >
struct iterators
{
  typedef T type;
};

//迭代器萃取机
template <class >
struct traits
{
  typedef typename T::type type;
};

//普通指针萃取机
template <class >
struct traits<T*>
{
  typedef T* type;
};

//获取萃取机类型
template <class >
typename traits<T>::type get(const T&)
{
  return typename traits<T>::type();
}

//类型重载函数
void fun(int)
{
  cout<<"This is Iterator"<<endl;
}
void fun(int*)
{
  cout<<"This is Pointer"<<endl;
}

int main()
{
  iterators<int> it1;
  int* it2;
  fun(get(it1)); //This is Iterator
  fun(get(it2)); //This is Pointer
  return 0;
}