text: 
  
  #include <vector>
  using namespace std;
  
  
  class MobilePhone;
  class Network
  {
  public:
  	Network();
  	virtual ~Network();
  
  	bool         addPhone(MobilePhone *phone);
  	MobilePhone *findPhone(long long number);
  
  	bool         makeCall(long long fromPhone, long long toPhone);
  
  private:
  	vector<MobilePhone *> phones;  // does not "own" phone - don't delete
  };
  
  