The Complex_CELL_CORE Class:

This is a pure virtual class where we define the core cell to hold a complex element.

class Complex_CELL_CORE{
    friend class Complex_POLY_CORE;
    friend istream& operator>>(istream& in, Complex_CELL_CORE& A)
      {A.grab(in); return(in);};
    friend istream& operator>>(istream& in, Complex_CELL_CORE* A)
      {A->grab(in); return(in);};
    friend ostream& operator<<(ostream& out,const Complex_CELL_CORE& A)
      {A.print(out); return(out);};
    friend ostream& operator<<(ostream& out,const Complex_CELL_CORE* A)
      {A->print(out); return(out);};
  public:
    virtual ~Complex_CELL_CORE(){};
    void load_element(Complex x){element = x;};
    virtual istream& grab(istream& in) = 0;
    virtual ostream& print(ostream& out) const = 0;
  protected:
    Complex element;
  };