SA-1, due Sep 23
Assignment
In class we saw a Counter that would increment up to a given limit, and then start over at 0 when that limit was reached. I said that this would be a useful part of a digital watch or timer.
This assignment is to write a DigitalTimer class
that creates objects that are digital timers with two fields:
hours and minutes. This timer represents
24-hour time, so the hours should take on values 00 through 23 and
the minutes should take on values 00 through 59.
Your DigitalTimer class should make public the following two constructors
and three methods. Note that two of these have preconditions. A precondition is something
that you may assume about the parameters. You need not test for it.
DigitalTimer class should consist
of two Counter objects, one
to represent the hours and the other to represent the minutes.
You should use most of the methods from the Counter class
that we saw in class to implement the methods for the DigitalTimer class.
Because methods of the Counter class do a lot of the work for you, none
of the DigitalTimer methods should be longer than a few lines of code.
Note that it is not a problem that the tick() and set()
methods appear in both
the is the Counter and DigitalTimer
classes. Java can tell which you mean by looking at the
type of the object before the dot when the method is called.
Include the code for the Counter.java
class and the
TimerDriver.java
class in your project along with
the DigitalTimer class that you put into the file
DigitalTimer.java. Running TimerDriver's
main method will test the correctness of your
DigitalTimer class.
Put your DigitalTimer.java file and a file containing the
the output of TimerDriver.java
(when in a project with your
DigitalTimer.java code and my Counter.java) into
a folder, zip them, and turn in the compressed file via Blackboard.