> What does the ^ do in your program.  I looked up the ^ symbol
> and it is a bitwise XOR.  Why do you have this on your examples,
> except the 7 one?   The  51^7 and 12^51 are even more confusing.

It is XOR.  He's using the the following properties of XOR:

A XOR 0 = A
A XOR A = 0
A XOR B = B XOR A
A XOR (B XOR C) = (A XOR B) XOR C

The effect of the code is
(Wo is original W)

W = Wo XOR 7    (0 if W == 7)
W = W XOR (51 XOR 7) or W = (Wo XOR 7) XOR (51 XOR 7)
which after rearranging is Wo XOR 51 (0 if Wo == 51).

This is a neat way of doing a switch BTW.

Orin.