# Testing for Zero Values

Reference > Science > Technology > Beginner Programming TipsSuppose you have 3 variables: X, Y and Z. And you want to find out if any of them are equal to zero. Here's how you might do it?

Dim X As Integer

Dim Y As Integer

Dim Z As Integer

'Check to see if any of X, Y or Z equal 0

MyBoolean = False

If X = 0 Then

If Y = 0 Then

If Z = 0 Then

MyBoolean = True

End If

End If

End If

Is that the quickest and easiest way to do it? No. Here's another way:

Dim X As Integer

Dim Y As Integer

Dim Z As Integer

'Check to see if any of X, Y or Z equal 0

MyBoolean = (X = 0) Or (Y = 0) Or (Z = 0)

Much shorter, much simpler. Is there a *shorter* way still of doing it?

Yes, there is. But before I give it to you, I have to warn you, there are some warnings and disclaimers that go with this method. So be sure to read the paragraphs *after* the code to find out what the disclaimers are.

Here's the code.

Dim X As Integer

Dim Y As Integer

Dim Z As Integer

'Check to see if any of X, Y or Z equal 0

MyBoolean = X * Y * Z

Why does this work? Because if any of X, Y, or Z is equal to 0, the whole equation is equal to zero, and we already know that the computer treats zero as a boolean *False*! If none of them are zero, then MyBoolean turns out to be a non-zero number, and the computer considers any non-zero number to have a truth value of *True*.

Now, what about those disclaimers? The first disclaimer is this: There is no guarantee that one method is quicker than another to execute. That is largely dependent on the variable types you are using. When I set X, Y, and Z to Long variables, the multiplication method was actually about 4 times as fast. However, when I set them to Double variable types, there was no signicant speed difference between the methods.

The second disclaimer is this: you should not do this unless you are *sure* that your variables X, Y, and Z are small numbers. What happens if X, Y, and Z all equal 100? When you multiply them as Integers, you get an *overflow* error!

And the third disclaimer is, this method is not as*readable*. In other words, when you come back to this line of code after five months, you're going to look at it and say "What in the WORLD does that line do?"

But even with all the disclaimers, and even though you probably won't ever do it in an honest-to-goodness program, it's still kind of a fun trick.

One more cute little trick. Suppose you wanted to check to find out if X = 0 or Y = 1. You could do it like this:

Dim X As Integer

Dim Y As Integer

'Check to see if X = 0 or Y = 1

MyBoolean = X * (Y - 1)

And why do you suppose that works? Because if Y equals one then (Y - 1) equals zero!

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