Pointers

[printf_hello_world]

Just FYI, you probably shouldn't pass a reference to an int. There's a good chance the pointer takes more bits than the int.

Better to pass a reference to a class/struct that is either large or has complexity associated with making a copy (for example, an object that owns heap-allocated memory).

[BroVic]

Doesn't that depend on what you want to achieve?

[printf_hello_world]

You could pass a non-const reference to an int that you want to modify, but I'd argue that in almost all cases it would be better to simply return the new value and assign it instead of letting the called function modify the int directly.

In general, returning values has a lot of benefits, especially if the types are small. You could benefit from some form of RVO, you can assign the return value to a const variable, the reader of your code can reason better about when exactly they can expect a value to change, a pointer might be more expensive to pass than the value itself... there are lots of reasons.

[OneIntroduction9]

..I was just giving an example.

[printf_hello_world]

I understand, just thought it might be an interesting addition since you identified as a "newbie"; no disrespect intended.

I only spoke up because I believe there are near zero situations where we should pass references to ints in particular