CPTR 124 Fundamentals of Programming

In this lab you will provide alternate implementations of the traffic light class given in Chapter 7.

  1. Teams

    You are encouraged to work with a partner for this lab. You and your partner should begin thinking about the problems and begin writing the code before lab time.

  2. Preparing your working folder

    Make a subfolder named Lab5 within your H:\cptr124 folder.

  3. Alternate traffic light implementation

    Do Exercise #10 in Section 7.6 in your textbook. In your new version you will use three Boolean variables to keep track of a light's state instead on the single integer value used in RYGTrafficLight. Name your new class AlternateTrafficLightYou will need to adjust the constructor and methods to work with this new representation. Your traffic light objects should behave identically to the RYGTrafficLight objects in the book.

  4. Adding novel behavior

    Create a new class named AugmentedTrafficLight. You may use either RYGTrafficLight from the book or your new AlternateTrafficLight as a starting point; that is, you decide how best to represent the state of this new kind of traffic light.

    AugmentedTrafficLights behave in an interesting way:

    • The arrangement of red, yellow, and green lamps is exactly the same as in RYGTrafficLight.

    • When the red lamp is illuminated all by itself, traffic facing the light must stop and wait. This is "stop" state.

      [(R) ( ) ( )]

    • Just before changing to green, this new kind of traffic light illuminates its yellow lamp while its red lamp remains on. This state means "get ready to go, but do not go yet." This state we will call the "get ready to go" state.

      [(R) (Y) ( )]

    • After the "get ready to go" state the green lamp is illuminated all by itself. This means it should be safe to proceed. This is the "go" state.

      [( ) ( ) (G)]

    • Towards the end of the "go" state the yellow lamp is turned on while the green lamp stays on. This is the "get ready to stop" state.

      [( ) (Y) (G)]

    • After the "get ready to stop" state the green lamp turns off leaving the yellow lamp on all by itself. This is the "stop is imminent" state.

      [( ) (Y) ( )]

    • After the "stop is imminent" state the light returns to "stop" state. The same cycle continues indefinitely.

      [(R) ( ) ( )]

  5. Check out

    Demonstrate that both of your traffic light objects work as they should and then print out the source code for your AlternateTrafficLight and AugmentedTrafficLight classes. Be sure your name is on each sheet and staple them together. If you worked with a partner, please submit only one set of printouts with both names on it.