berikut ini memberikan solusi sehingga untuk menambahkan enum baru hanya memerlukan satu baris edit, pekerjaan yang mirip dengan menambahkan satu baris dalam daftar enum {}.
//------------------------------------------------------------------------------
// enum to string example
#define FOR_EACH_GENDER(tbd) \
tbd(GENDER_MALE) \
tbd(GENDER_FEMALE) \
tbd(GENDER_INTERSEX) \
#define ONE_GENDER_ENUM(name) name,
enum
{
FOR_EACH_GENDER(ONE_GENDER_ENUM)
MAX_GENDER
};
#define ONE_GENDER(name) #name,
static const char *enumGENDER_TO_STRING[] =
{
FOR_EACH_GENDER(ONE_GENDER)
};
// access string name with enumGENDER_TO_STRING[value]
// or, to be safe converting from a untrustworthy caller
static const char *enumGenderToString(unsigned int value)
{
if (value < MAX_GENDER)
{
return enumGENDER_TO_STRING[value];
}
return NULL;
}
static void printAllGenders(void)
{
for (int ii = 0; ii < MAX_GENDER; ii++)
{
printf("%d) gender %s\n", ii, enumGENDER_TO_STRING[ii]);
}
}
//------------------------------------------------------------------------------
// you can assign an arbitrary value and/or information to each enum,
#define FOR_EACH_PERSON(tbd) \
tbd(2, PERSON_FRED, "Fred", "Weasley", GENDER_MALE, 12) \
tbd(4, PERSON_GEORGE, "George", "Weasley", GENDER_MALE, 12) \
tbd(6, PERSON_HARRY, "Harry", "Potter", GENDER_MALE, 10) \
tbd(8, PERSON_HERMIONE, "Hermione", "Granger", GENDER_FEMALE, 10) \
#define ONE_PERSON_ENUM(value, ename, first, last, gender, age) ename = value,
enum
{
FOR_EACH_PERSON(ONE_PERSON_ENUM)
};
typedef struct PersonInfoRec
{
int value;
const char *ename;
const char *first;
const char *last;
int gender;
int age;
} PersonInfo;
#define ONE_PERSON_INFO(value, ename, first, last, gender, age) \
{ ename, #ename, first, last, gender, age },
static const PersonInfo personInfo[] =
{
FOR_EACH_PERSON(ONE_PERSON_INFO)
{ 0, NULL, NULL, NULL, 0, 0 }
};
// note: if the enum values are not sequential, you need another way to lookup
// the information besides personInfo[ENUM_NAME]
static void printAllPersons(void)
{
for (int ii = 0; ; ii++)
{
const PersonInfo *pPI = &personInfo[ii];
if (!pPI->ename)
{
break;
}
printf("%d) enum %-15s %8s %-8s %13s %2d\n",
pPI->value, pPI->ename, pPI->first, pPI->last,
enumGenderToString(pPI->gender), pPI->age);
}
}