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

An Ounce of Prevention
As you write your code, you can use several techniques to help you catch
bugs as you type. These techniques will not pre vent all bugs, but they will cut
down on the num ber you have to find later. If you are perfect and never make
mistakes, these techniques won’t affect any thing. The techniques are for hu man
eyes; the computer will be able to run your code without them. But for those of
us who are not perfect, our hu man eyes need all the help we can get to catch bugs
or pre vent them from happening.
Cap i tal iza tion
You might have looked at some of the ex amples and won dered why certain
things were cap italized in certain ways. Some of it is part of the technique to pre-
vent bugs, and some of it is forced upon you by VBA. There are five kinds of
things you can type into the VBA Editor:
1. Comments
2.
Text between quotes
3. Variable names
4.
Pro ce dure names
5.
VBA stuff (built-in func tion names, pro cedure names, ob ject names,
etc.)
Comments can be cap italized any way that you like because they are for
you to read. Pay close at tention to capitalization of text be tween quotes be cause
that will usually be dis played for your students, but for the pur poses of de bug-
ging, it doesn’t mat ter how you cap italize it. Cap italization of the last three items 
can be important for debugging.
In this book, I have used the fol lowing con vention: Variable names be gin
with a lowercase let ter; and procedure names be gin with an up percase let ter.
Furthermore, since variable names and procedure names can not con tain spaces,
any new word in the name be gins with an up percase letter. This is a convention,
a technique, a trick. I could have used
yourName
in stead of 
YourName
and
UserName
in stead of 
userName
. It would have worked fine. How ever, if you
use this convention, you can look at your code and always tell whether a name
162 De bug ging Tips

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re fers to a vari able or a pro ce dure by look ing at the cap i tal iza tion. Cap i tal iz ing
the first letter of each sub sequent word in a variable or pro cedure name simply
helps you read it more easily. You want to be able to read the names because you
picked names that make sense to you.
You should be able to tell immediately that the following are vari ables, and
you prob 
ably even have a reasonable idea of what in 
formation they hold: