On how many projects where you have to have tonnes of classes to make it just runnable did you work?
I cannot believe you that you manage those without making those logical mistakes at least sometimes.
I'm relatively new to programming in general so the answer would be not many, however I'm currently working on two libraries where one is being designed based on the design of the other. So far (I've finished about 10 classes and working on 8 more at the moment) I haven't made any logical mistakes (I've done some testing). My only problem is getting confused with what I've completed, as I have to work on multiple things at once and refactor as I go along. I guess that just comes down to poor organisation of my time.
Regarding previous projects, I've never made a mistake where I've mistyped something. The mistakes I make are usually forgetting a line, or a wrongly used operator (e.g
<= instead of <).