/**
 * A collection of functions for determining how much mp3 music can
 * fit on various-sized discs/devices.
 *
 * @author Ian Barland
 * @version 2006.Sep.11
 */
class Mp3_Size {

  
  /** How many minutes of mp3 music which can be stored in 1Gig (approx). */
  final double MINS_PER_GIG   = 940.0;  

  /** The number of minutes on an album (approx). */
  final double MINS_PER_ALBUM =  45.0;

  
  /**
   *  return The number of minutes of mp3 music which can fit into `size'.
   * @return The number of minutes of mp3 music which can fit into `size'.
   * @param size The amount of storage space, in GB.
   */
  double gbToMins( double size ) {
    return size * MINS_PER_GIG;
    }

  
  /**
   *  return The number of *complete* albums which can fit into `size'.
   * @return The number of *complete* albums which can fit into `size'.
   * @param size   An amount of storage space, in GB.
   */
  int gbToAlbums( double size ) {
    return doubleToInt( Math.floor( gbToMins(size) / MINS_PER_ALBUM ) );
    }



  /**
   * Print to the screen, a message about how much music `d' can hold.
   * (No return value.)
   * @param d   An amount of disc space, in GB.
   */
  void printAnAdvertisingSpec(double d) {
    System.out.println( "A " + d + " GB disk can hold "
                        + gbToAlbums( d ) + " albums." );
    }

  
  /**
   * Print to the screen, messages about how much mp3 music can fit
   * on to various disc sizes.
   * Suitable for printing on a screen seen by customers.
   */
  void printManyAdvertisingSpecs() {
  
    double discSize = 0.0;  // A variable just to hold various sizes.
    printAnAdvertisingSpec( discSize );
  
    discSize = 8.0;
    printAnAdvertisingSpec( discSize );
    
    discSize = 0.5;
    printAnAdvertisingSpec( discSize );
    
    discSize = 3.0;
    printAnAdvertisingSpec( discSize );
    
    discSize = Math.pow( 3, 2 );
    printAnAdvertisingSpec( discSize );
    }
  
  
   /**
    *  return an integer close to `d' (not specified as rounding up or down though).
    * @return an integer close to `d' (not specified as rounding up or down though).
    * @param d   A double to be converted.
    *
    * WARNING: If d is outside of plus/minus 2.15billion (or so),
    * this program will silently return a wildly incorrect answer!
    */
   int doubleToInt( double d ) {
     /* Turn d into an int by casting it.
      * (You can look up 'casting' in the book.)
      */
     return (int) d;
     }
    
    
  }