First, I would like to clarify my question here. During my coding development, I found myself passing by reference in my class member functions except for those built-in types. But I have an idea in my mind why wouldn't I use a pointer to pass in an argument (passing by pointers).
Is it a bad practice to pass by reference not passing by pointers?
One common style is to pass input arguments by const reference, and output arguments by pointer. In this style, we don't pass output arguments by non-const reference to more clearly delineate input from output arguments.