Java Reference
In-Depth Information
Display 6.6
Display 6.4 Redone Using the Class
PartiallyFilledArray
(part 2 of 2)
41
/**
42
Returns the average of numbers in the PartiallyFilledArray a.
43
*/
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public static double
computeAverage(PartiallyFilledArray a)
45
{
46
double
total = 0;
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for
(
int
index = 0; index < a.getNumberOfElements(); index++)
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total = total + a.getElement(index);
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if
(a.getNumberOfElements() > 0)
50
{
51
return
(total/a.getNumberOfElements());
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}
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else
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{
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System.out.println("ERROR: Trying to average 0 numbers.");
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System.out.println("computeAverage returns 0.");
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return
0;
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}
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}
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/**
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Gives screen output showing how much each of the
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elements in the PartiallyFilledArray a differ from the average.
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*/
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public static void
showDifference(PartiallyFilledArray a)
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{
66
double
average = computeAverage(a);
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System.out.println("Average of the " + a.getNumberOfElements()
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+ " scores = " + average);
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System.out.println("The scores are:");
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for
(
int
index = 0; index < a.getNumberOfElements(); index++)
71
System.out.println(a.getElement(index) + " differs from average by "
+ (a.getElement(index)
−
average));
72
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}
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}
cycle through all the elements of a collection object with this kind of
for
loop, because
these collection classes normally do not have indices associated with their elements, as
an array does.
4
However, starting with version 5.0, Java has added a new kind of
for
loop that can cycle through all the elements in a collection even though there are no
4
You can construct a similar
for
loop using something called an
iterator
in place of the array index,
but we will not go into that until later in this topic.
