Create main.cpp

It's the start of the log in section for a text based notepad that is password protected. So only a user can enter, read, edit notes. Eventually I'm going to remake program with a gui and or android format. I've already started my android version but mainly focusing on c++ language. Once I learn c++ I want to take on java. I'm sure there are bugs in the program but like I said I'm still learning c++.