Powerful PowerPoint for Educators: Using Visual Basic for Applications to Make PowerPoint Interactive

Figure 8.2. VBA Code for Se lecting Five Questions from a Pool of Questions
This pre sentation con sists of a ti tle slide, a last slide, and as many ques tion
slides as we want. The ti tle slide has a but ton that is tied to the 
GetStarted
pro -
cedure. The question slides have buttons for right and wrong answers that are
tied to the 
RightAnswer
and 
WrongAnswer
pro ce dures, re spec tively. The last
slide has a but ton that is hyperlinked to the first slide (no VBA) and plays the ap -
plause sound. This version does not keep score.
Choose Ques tions Randomly from a Pool 147

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The key el ements of this pre sentation are the array
vis 
ited
and the pro ce-
dure
RandomNext
.
vis 
ited
has an el ement for each question. Actually, it has
an el ement for each slide, but the first and last elements are ignored. The el e-
ments are each set to 
False
in 
Ini 
tial 
ize
. When a ques tion is an swered cor-
rectly, the element of
vis 
ited
for that ques 
tion is set to 
True
in the
RightAnswer
pro cedure. In ad dition, one is added to 
numRead
, a variable that
keeps track of how many questions have been read.
RandomNext
is used to go to the next ques 
tion in 
stead of
ActivePresentation.SlideShowWindow.View.Next
. In the past, the
next question has al ways been the next slide. Now, we want to randomly select a
slide, so we can’t simply go to the next slide.
RandomNext
first checks to see
whether we have an swered five or more questions. Just in case the presentation
doesn’t have five questions, it also checks to be sure we have n’t an swered as
many questions as there are: