What's the reasoning behind putting constants in if statements first?

Question

I was looking at some example C++ code for a hardware interface I\'m working with and noticed a lot of statements along the following lines:

if ( NULL == pMsg )          


        

Answer 1

So that you don't mix comparison (==) with assignment (=).

As you know, you can't assign to a constant. If you try, the compliler will give you an error.

Basically, it's one of defensive programming techniques. To protect yourself from yourself.