a + b + c = -1

--
Regards,
Tom Ogilvy



"Frederick Chow" wrote:

Hi all,

Sorry first that my question may not be specifically related to Excel VBA,
but I really encountered it when I had to write a VBA function.

Suppose I have three boolean variables A, B and C. How can I test if there
is exactly one of them is true? I found that the following expression

A Xor B Xor C

failed when A = True and B = True and C = True.

Any ideas would be greatly appreciated.

Frederick Chow
Hong Kong.