Enumerated types

C lets you define enumerated types:

enum { green, violet, indigo, lilac } colour; /* define `enum colour' */ enum colour a_particular_colour = violet;

The definition of the type (here enum colour) must occur before its first use:

enum { green, violet, indigo, lilac } colour; /* define enum colour */ /* .. */ int is_purplish(enum colour c) { if (c == violet || c == indigo || c == lilac) { return 1; } else { return 0; } }