C++ Primer Plus

Setting Enumerator Values

You can set enumerator values explicitly by using the assignment operator:

enum bits{one = 1, two = 2, four = 4, eight = 8};

The assigned values must be integers. You also can define just some of the enumerators explicitly:

enum bigstep{first, second = 100, third};

In this case, first is 0 by default. Subsequent uninitialized enumerators are larger by one than their predecessors. So, third would have the value 101.

Finally, you can create more than one enumerator with the same value:

enum {zero, null = 0, one, numero_uno = 1};

Here, both zero and null are 0, and both one and numero_uno are 1. In earlier versions of C++, you could assign only int values (or values that promote to int) to enumerators, but that restriction ...