What's the best way to remember/understand the codes?

Answer 1

How to remember:
1.) Use them ALOT
2.) Study then when you dont remember
3.) flash cards (that usually helps)
4.) Books(books and google will be your best friend from now on)

Hope i was helpful to you :)

Answer 2

"Practice makes perfect".

Answer 3

I never can remember codes, even the ones I make :P I usually just restart them from scratch; I find it more fun that way and it gives me the chance to better improve on something already created. If it's a much longer piece, then I just copy/paste from a previous project. (This is only OK if you own the original code!)

Using others' code as reference will help you understand more. A good programmer will often comment their code to help peer reviewers understand what's going on in each line. Don't necessarily copy what you see others do; you don't learn anything that way. Look at the methods others use to solve certain problems and modify their methods to suit your needs best. (be sure to give credit if someone else's work helps solve your problem!)