When I write code, I try to group lines of similar code together, then leave a blank line and write another block.
I believe this contributes to the neatness and readabi
Your teacher was probably half right in that in the real World you won't have the line spacing. Certainly on the Big Ball of Mud code bases I come across you're lucky if you get a line space let alone comment of explanation.
As an aside the 73 year old programmer that wrote most of this Big Ball of Mud is still working there and his explanation is that the binaries need to be kept as small as possible, I didn't bother to check whether the compilers of 20 to 30 years ago were that inefficient they couldn't strip whitespace but I'm somewhat skeptical.
I use single blank lines to break up logical sections in my own code as I find it greatly enhance readability.
As always the best test with these type of readability concerns is to grab some tricky piece of code you wrote and haven't looked at for over a year and see if you can get a grasp on it quickly. If you can then your code will be better than most of what you'll see in the real World!