Programming and Problem Solving with Java

CASE STUDY^673

The next three responsibilities are within the event handler and can be grouped to-
gether.

Have we forgotten anything? Yes—how are we going to count the number of compar-
isons? We can derive a class from one of the list classes and have it override the isThere
method. Before we do that, let’s spend a minute thinking about the processing that we
need to do. We don’t delete an item, and we don’t use any of the observers. In fact, we
aren’t really dealing with a list at all, because the number of items is a constant. It
would be much more efficient to just generate the random numbers directly into an ar-
ray, and then write an isTheremethod that searches the array and counts the number
of comparisons. We can borrow the code from one of our list classes. We use the linear
search because the array items are not in sorted order.

We have to make countbe a field in the applet class. We need two outputs from our
isTheremethod (foundand count), yet the returnstatement can only return one value.

Is there (item)

Set location to 0

Set found to false

Set count to 0

Set moreToSearch to (location less than SIZE)

whilemoreToSearch and !found

Increment count

ifitem equals values[location]

Set found to true

else

Increment location

Set moreToSearch to (location less than SIZE)

returnfound

Generate list (revised)

forcounter going from 0 to SIZE – 1

values[counter] = Math.abs(rand.nextInt()) % 1000

Event handler

Get item

Search list for item

iffound

Write item, " is in list found with ", count, " comparisons"

else

Write item, " is not in list, determined with ", count, " comparisons"