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variable (assume zero degrees if no value is specified and Celsius if no scale is speci-
fied), one with two parameters for the two instance variables, and a no-argument
constructor (set to zero degrees Celsius). Include the following: (1) two accessor
methods to return the temperature—one to return the degrees Celsius, the other
to return the degrees Fahrenheit—use the following formulas to write the two
methods, and round to the nearest tenth of a degree:
-
DegreesC
=
5
1
degreesF
32
2
/9
+
DegreesF
=
(9
1
degreesC)/5)
32;
(2) three mutator methods: one to set the value, one to set the scale (
F
or
C
), and
one to set both; (3) three comparison methods: an
equals
method to test whether
two temperatures are equal, one method to test whether one temperature is greater
than another, and one method to test whether one temperature is less than
another (note that a Celsius temperature can be equal to a Fahrenheit temperature
as indicated by the above formulas); and (4) a suitable
toString
method. Then
write a driver program (or programs) that tests all the methods. Be sure to use
each of the constructors, to include at least one true and one false case for each of
the comparison methods, and to test at least the following temperature equalities:
0.0 degrees C = 32.0 degrees F, -40.0 degrees C = -40.0 degrees F, and 100.0
degrees C = 212.0 degrees F.
8. Redefine the class
Date
in Display 4.13 so that the instance variable for the month
is of type
int
instead of type
String
. None of the method headings should change
in any way. In particular, no
String
type parameters should change to
int
type
parameters. You must redefine the methods to make things work out. Any program
that uses the
Date
class from Display 4.13 should be able to use your
Date
class
without any changes in the program. In particular, the program in Display 4.14
should work the same whether the
Date
class is defined as in Display 4.13 or is
defined as you do it for this project. Write a test program (or programs) that tests
each method in your class definition.
9. Define a class whose objects are records on animal species. The class should have
instance variables for the species name, population, and growth rate. The growth
rate is a percentage that can be positive or negative and can exceed 100%. Include
a suitable collection of constructors, mutator methods, and accessor methods.
Include a
toString
method and an
equals
method. Include a
boolean
valued
method named
endangered
that returns
true
when the growth rate is negative
and returns
false
otherwise. Write a test program (or programs) that tests each
method in your class definition.
10. Your vet's office is using the
Pet
class defined in Display 4.15 and would like to
include a way to calculate the dosage amount for drugs that are commonly admin-
istered for dogs and cats. Make the following modifications to the class:
•
Add an instance variable that indicates if the type of the pet is a dog or a cat.
•
Modify the constructor and the set method to include the type of pet (i.e.,
dog or cat).
VideoNote
Solution to
Programming
Project 4.9
