#ifndef ATOM_H
#define ATOM_H

using electron = int;
using   proton = int;

template <int Z>   //Z is the atom number of the element.
class atom {
private:
	electron electrons[Z];
	proton protons[Z];
public:
	atom() {}

	static int period() {   //which row of the periodic table?
                int p {1};
                for (; Z > 2 * p * p; ++p) {
                }
                return p;
        }
};

using hydrogen = atom<1>;
using helium   = atom<2>;
using oxygen   = atom<8>;

#endif