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Answers to Questions and Exercises: Object-Oriented Concepts

Answers to Questions

1. Question: The ClickMe applet uses Color.red to set the drawing color to red. What other colors can you get by name like this?
   Answer: Color.black, Color.blue, Color.cyan, Color.darkGray, Color.gray, Color.green, Color.lightGray, Color.magenta, Color.orange, Color.pink, Color.white, and Color.yellow

2. Question: How would you specify other colors, like purple?
   Answer: You specify them using the RGB (red-green-blue) color model. In RGB, purple is: 0.5, 0.0, 0.5

Answers to Exercises

To read explanations about the solutions and to run the resulting applets, see Run the ClickMe Applets.

1. Exercise: Modify the applet to draw a green square instead of a red spot.
   Answer: Look at our solution, contained in the ClickMeGreen.java source file.

2. Exercise: Modify the applet to display your name in purple instead of a red spot.
   Answer: Look at our solution, contained in the ClickMePurple.java source file.

Answers to Extra Credit Exercises

To read explanations about the solutions and to run the resulting applets, see Run the ClickMe Applets.

1. Exercise: Modify the applet to erase the red spot instead of redrawing the whole applet.
   Answer: Look at our solution, contained in the ClickMeErase.java source file.

2. Exercise: Modify the applet to drag the red spot when the mouse is held down.
   Answer: Look at our solution, contained in the ClickMeDrag.java source file.

3. Exercise: Starting with your solution to the previous exercise, change the applet into a "scribble" applet, which draws as the mouse is dragged.
   Answer: Look at our solution, contained in the ClickMeScribble.java source file.

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