References
A reference is declared by using the ampersand.
int i = 7; int & j = i; // j is an alias for i j++; // i is now 8 i += 3; // i is now 11, as is j
A reference can be target of an assignment. Some functions will return a reference as a result for precisely this reason.
int values[100]; int & index(int i) { return values[i + 2]; } index(27) = 12; // changes values[29];