int i = 42, *p = &i, &r = i;

decltype (*p) c; // error: c is int& and must be initialized

Above is the an example of C++ decltype. I know with the asterisk*, we are dereferencing the pointer p and we get the object to which the pointer p points. But how does decltype (*p) end up with an int& type, but not a plain int?

Thank you, will upvote for a detailed answer.