I do not understand long articles about differences between variables, references, pointers
But those that do support references always require that the reference is always filled with value to some existing objects (i.e. some address). Pointers on the other hand can contain a special value named nil, NULL, nullptr or the like that says "pointing to nowhere".
so now I know one difference between pointer and reference
Are there any other differences without an long explanation that I do not understand yet.