14.6. Increment and Decrement Operators

The increment (++) and decrement (--) operators are most often implemented for iterator classes. These operators let the class move between the elements of a sequence. There is no language requirement that these operators be members of the class. However, because these operators change the state of the object on which they operate, our preference is to make them members.

For the built-in types, there are both prefix and postfix versions of the increment and decrement operators. Not surprisingly, we can define both the prefix and postfix instances of these operators for our own classes as well. We’ll look at the prefix versions first and then implement the postfix ones.