goals: decoupled

Arithmetic

// 24 == 3 * (2^3) 
// prime numbers: 2 & 3

Algebra

// (x+2) * (x-1) * (2*x-5)  ==  2*x^3 - 9*x^2 + 6*x + 10 

// mathematically these are prime "numbers": 
//  (x+2) 
//  (x-1) 
// (2x-5)

Code

struct PhoneCall { 
  void act(Connection*); 
  Connection*   answer(); 
  Connection*   call(PhoneNumber); 
  void          endcall(); 
  PhoneNumbers  assist(string); 
  PhoneNumbers  assist(long); 
  int     push(Message);// return queue length. 
  Message pop(); 
}; 

struct Playlist { 
  void    act(Song*); 
  Songs match(string) const; 
  Songs match(Midi)   const; 
  Song pop(); 
  int push(Song); // return queue length. 

};