Does this mean if I write code that does X at company A, and then move to company B and am asked to write code that does X, I would be copyright infringing my o

Does this mean if I write code that does X at company A, and then move to company B and am asked to write code that does X, I would be copyright infringing my own code I wrote at company A unless I purposely went out of my way to write it completly differently? Because chances are I still remember how I did it, or even if I don't, chances are I'll come up with pretty much the same way, as it's inherent to my code style and thought process. I guess it's something I'll be taking great care in doing if this ever happens to me.