Enums (enumerations) are user-defined types that consist of named integer constants.
enum Color { RED, GREEN, BLUE };
enum Weekday { MONDAY = 1, TUESDAY = 2, WEDNESDAY = 3, THURSDAY = 4, FRIDAY = 5 };
enum Color favorite_color = BLUE; if (favorite_color == RED) { printf("Your favorite color is red\n"); }
printf("Size of enum: %zu\n", sizeof(enum Color));