CODEWITHSUNDEEP
cenums
David
David

Reputation: 23

enum associated values in c

I have an enum declaration as:

enum qty { cars = 10, bikes = 9, horses = 9 ... } // total 28

How could I add up all the associated values of enumerator-list?

Upvotes: 2

Views: 906

Answers (5)

doynax
doynax

Reputation: 4465

If you've got an awful lot of these to keep in sync then some preprocessor abuse might come in handy:

#define SUM(name, count) + (count)
#define DEF(name, count) name = (count),

enum qty
{
#   define QTY(f) \
    f(cars,  10)  \
    f(bikes,  9)  \
    f(horses, 9)

    QTY(DEF)

    total = 0 + QTY(SUM)
};

Upvotes: 0

JustJeff
JustJeff

Reputation: 12980

In C, enums are just mapped to integers. They're not even typesafe, as you can freely substitute members of one enum in places intended for other enums.

Upvotes: 1

progrmr
progrmr

Reputation: 77291

There's no way to loop thru them in C (you could in Ada ;-) so this is all you can do:

int sum = cars + bikes + horses + ...;

but like zneak and Tyler said, you're probably not using the right construct.

Upvotes: 1

zneak
zneak

Reputation: 138251

You can't know at runtime the contents of an enum in C.

Besides, this sounds like a misuse of enumerations. You should use them to define constants that you will use inside your code, not to store quantities or stuff like that which should otherwise be variable: enumeration values are immutable. Use integer arrays for that purpose; you can loop through these.

Upvotes: 5

msw
msw

Reputation: 43527

There is no way to express "for all enums in qty" in C.

Upvotes: 3

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