METHODS AGAIN

- why methods?
  1) modularity
     - group together some statements that do something 
       useful
     - goal to reuse them
  2) interact with objects
     - want object to worry about functionality, so that as 
       object user, we don't have to
     - methods make objects do things
     - get information from them

Example:
- no params, no return values
- have an object remember something for you

  /* We're playing Alpha Centauri... we have to keep track 
     of how many turns have passed */
  void passTurn()

  // body
  GameTime acTurns = new GameTime();
  // this will happen on a regular basis
  acTurns.passTurn();

Example:
- params only
- make an object interact with your application user

  /* increase the brightness of the screen by degree
     note that brightness is on a saturating scale of 
     0 to 100 */
  void brighten(int degree)

  // body
  Background bg = new Background();
  ...
  // user's wearing sunglasses
  bg.brighten(100);

Example:
- return value only
- get some information that the object's been remembering  
  for you, when you actually need it

  /* How many coins does Mario have? */
  int getNumCoins()

  MarioPoint mp = new MarioPoint();
  // User pressed pause, need to display number of coins
  displayCoins(mp.getNumCoins());

Example:
- params and return value
- calculate something, but make this dynamic

  /* Calculate least common denominator */
  int lcd(int a, int b)

  // maybe you want to build a math program
  Scanner stdin = new Scanner(System.in);
  System.out.println("First int?");
  int i1 = in.nextInt();
  System.out.println("Second int?");
  int i2 = in.nextInt();
  System.out.println("lcd is: " + lcd(i1, i2) );