I'm getting:

error: default argument for template parameter for class enclosing 'ticker::garbage_element'
   51 | E ticker ::garbage_element;
      |                   ^~~~~~~~~~~~~~~

l know if I use the keyword "inline" like this:

    inline static  E garbage_element;

inside the "ticker" template, it compiles fine, but how in the world it suppose to look like outside the template.

#include 
#include 

template< template class T, class E, class A = std::allocator  >
class ticker
{
    T* container;
    int current_index;
    bool mode;
    static  E garbage_element;
 public:
    // constructors and members fn
};

template< template class T, class E, class A = std::allocator >
E ticker ::garbage_element;