Coin flipping: .contains() method and keeping a counter - 09/16-18/2002

1. Press down your mouse button down inside the circle to flip the coin, getting Heads or Tails. Click outside the coin graphic to see the miss recorded. Perhaps the coin rolled off the table, so we need to toss it again.

2. Here is the Java code. You received this or will receive this as a handout. It contains techniques and concepts helpful to doing your current Java assignment, the laundry sorter.

   import objectdraw.*;
   import java.awt.*;
   
   public class CoinFlipSimulator extends WindowController {
   
      private static final int heads = 1;   // These are constants.
      private static final int tails = 2;   // The value is final
                                            // and it cannot change
                                            // or vary like a variable's can.
      private FilledOval coin;
      private Text coinFace;
   
      private int headsCount;
      private int tailsCount;
      private int missdCount;
   
      private Text headsReport, 
                   tailsReport,
                   missdReport;
   
      private Location headsTailsLocation;
   
      private RandomIntGenerator generator;  // has to be declared out here
                                             // as an instance variable.  Why?
      public void begin()
      {
          headsCount = 0;
          tailsCount = 0;
          missdCount = 0;
   
          coin = new FilledOval(75, 100, 100, 100, canvas);
          coin.setColor( new Color(255, 204, 0 ) );
          new FramedOval(75, 100, 100, 100, canvas);
          coinFace = new Text("Click to Flip", 93, 143, canvas);
          coinFace.setBold();
   
          headsTailsLocation = new Location( 107, 143 );
          
          headsReport = new Text("Heads:  0",  125, 220, canvas); 
          tailsReport = new Text("Tails:  0",  125, 240, canvas);
          missdReport = new Text("Missed: 0", 125, 260, canvas);
          missdReport.setColor( Color.red );
   
          generator = new RandomIntGenerator(1, 2);  // Create the random 
                                                     // generator that only
                                                     // does 2 values, 1 and 2.
      }
   
   
      public void onMousePress(Location point) 
      {
         int flipValue;   // local integer variable for
                          // holding the result of the 
                          // coin flip, Heads or Tails, 1 or 2
   
         String coinMessage;    // local String object variable.
   
         if ( coin.contains(point) )
         {
            flipValue = generator.nextValue();    // Generates a random 
                                                  //   integer 1 (H) or 2 (T).
            if (flipValue == heads)
            {
               coinMessage = "Heads";
               headsCount = headsCount + 1;
               headsReport.setText( "Heads:  " + headsCount );
            }
            else // if (flipValue == tails)
            {
               coinMessage = "Tails";
               tailsCount = tailsCount + 1;
               tailsReport.setText( "Tails:  " + tailsCount );
            }
   
            coinFace.moveTo( headsTailsLocation );
   
            coinFace.setText( coinMessage );
         }
         else
         {
            missdCount = missdCount + 1;
            missdReport.setText("Missed: " + missdCount);
         }
      }
   }
   

3. How would you modify or add to the above code so that there was a BLUE rectangle with the words "Reset Counts" displayed in the middle of the BLUE rectangle?

   Now that you have added to code to display the BLUE rectangle with its "Reset Counts" message, add the Java code so that a Click event (or an onMousePress() event, if you prefer), would cause the Heads and Tails and Missed messages and the corresponding int counter variables to all be reset to or display 0?

   Check it out: See the Java Applet and try it out. It has all the above features, plus some surprising extras.

4. See you in class on Wednesday. Biction is one of the five essential ingredients to being a good programmer. As the semester continues, the other four will probably be mentioned. Surprisingly, they tie in with Ghostbusters too, as do all things related to programming and problem solving.