622: Mainline

At this point, you have the following definition for the one-argument engine constructor:

class engine {
  public: engine ( ) { }
          // New constructor:                                    
          engine (char *input_buffer) {                          
            // Create new array just long enough:                
            serial_number = new char[strlen(input_buffer) + 1];  
            strcpy (serial_number, input_buffer);                
          }                                                      
          virtual char* short_name ( ) {return "eng";} 
};