Yes I know, but it is for training and for adding some experience after 2 years of self learning. I have already build a regulator with 317 and 337 and I had an unpleased surprise : I bought 2 LM337 from the same place but after building and testing the circuit, the voltage reference of those two was 0.7V instead of 1.25. Yesterday i bought another one frome another store and now the reference is 1.12V which I think is not perfect but at least is not 0.7V. Now, as I said I want to build this circuit and see how it works.
Thank you again for everything.