Side Effecting Functions are Code Smells

I know the title might catch a few people off guard, but let me explain. Side effecting functions, for the most part, are code smells. This is a very important concept in Domain Driven Design (DDD) that's often overlooked. For those who are deep in DDD, this should sound rather familiar. And in the end, I think Spec# and some Design by Contract (DbC) constructs can mitigate this, or you can go the functional route as well. What Is A Side Effect? When you think of the word side effect i