Final answer:
In C++, reference variables are always aliases to other existing variables. Once a reference is initialized, it becomes another name for the variable it was initialized with, reflecting any changes to the original directly.
Step-by-step explanation:
In C++, reference variables are always aliases for other variables. When you declare a reference, you must immediately initialize it to be an alias for another already-existing variable. For example, if we have int a = 10; and then declare int& ref = a;, the 'ref' becomes another name for 'a', and any changes to 'ref' will also affect 'a'. This is because the reference 'ref' is not a separate variable; it is simply another way to refer to 'a'. In summary, references are a category of variable that, by definition, always serve as aliases to other variables.