Enumerations have the same representation as signed integers. Enumerations are handy for describing subsets of the integers. Enumerated data is declared as follows:
enum { name-identifier = constant, ... } identifier;
For example, the three colors red, yellow, and blue could be described by an enumerated type:
enum { RED = 2, YELLOW = 3, BLUE = 5 } colors;
It is an error to encode as an enum any other integer than those that have been given assignments in the enum declaration.