Java Reference
In-Depth Information
Display 13.6
Sorting Arrays of
Comparable
(part 2 of 2)
Sample Dialogue
Before Sorting
10.0, 9.0, 8.0, 7.0, 6.0, 5.0, 4.0, 3.0, 2.0, 1.0,
After sorting:
1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0,
Before sorting;
dog, cat, cornish game hen,
After sorting:
cat, cornish game hen, dog,
Self-Test Exercises
These exercises are for the material on the
Comparable
interface.
5. The method
interchange
in Display 13.5 makes no use of the fact that its
second argument is an array with base type
Comparable
. Suppose we change
the parameter type
Comparable[]
to
Object[]
and change the type of the
variable
temp
to
Object
. Would the program in Display 13.6 produce the
same dialogue?
6. Is the following a suitable implementation of the
Comparable
interface?
public class
Double2
implements
Comparable
{
private double
value;
public
Double2(
double
theValue)
{
value = theValue;
}
public int
compareTo(Object other)
{
return
-1;
}
public double
doubleValue()
{
return
value;
}
}
You can think of the underlying “comes before” relationship as saying that for
any objects
d1
and
d2
,
d1
comes before
d2
.
