When do you use "if ( a = b )"? (was Re: Funny mistake)

[john c chu]

In article <775 at camco.Celestial.COM> bill at camco.Celestial.COM (Bill Campbell) writes:
[concerning "if ( a = b )"
>Certainly it
>is a legal construction, but 90% of the time when I do this it
>was my mistake!

It's been my mistake everytime I've done it!! I realize that it is a
legal construction and I know what it does, but I was wondering...
Is there a good use for this?

					john
				chu at autarch.acsu.buffalo.edu