The #include lines at the top bring in libraries (like iostream for input and output).
Knowing exactly what a file does (e.g., user_auth.cpp vs main(1).cpp ). main(1).cpp
The filename main(1).cpp is almost never intentional. It is typically a byproduct of an operating system's file management system. When a user downloads or saves a file named main.cpp into a folder where a file with that name already exists, the system appends a suffix— (1) —to prevent overwriting the original. The #include lines at the top bring in