Thanks for the reply :D
In my school teachers let the students work with others and see their code,
but they do 2 things :
1 - They have a software that looks for all the projects to see if there is a
Plagiarism, or better, if anyone just made any copy-paste.
2 - They will ask individually every student questions about the code of
their project to see if they are able to do it, or if they barely made a copy
from some site and don't even understand how it works at all.
So even if it is not the best solution, I think that they are a little bit
more permissive in this area than many, which is somehow nice.
For example I received a lot of emails from students that don't graduated at
a specific course, sending me an email so I can send them my whole project. I
really want to, but I know that they will just copy-paste the code without
learning how it works, so I am really divided with "Share the Code to help
your neighbour", and "Do not share the code because they will not learn how
to do it after that by themselves, but propose your help for the project and
anything that they need with programming and others".
Thanks once again for your suggestions and your support :D