typedef enum {
    Sun,
    Mon,
    Tue,
    Wed,
    Thu,
    Fri,
    Sat,
} DaysOfWeek;

DaysOfWeek d;

int main(int argc, char** argv) {

    if (d == Sun) {
	// Do Sunday processing
    }
    if (d == Mon) {
	// Do Monday processing
    }
    // etc. for other days.

    /* Here's the normal way to assign an enum value to a variable. */
    d = Wed;

}