Getting total number of enum items

Question

Is it possible to get the total number of items defined by an enum at runtime?

While it's pretty much the same question as this one, that question relates to C#, and as far as I can tell, the method provided there won't work in Objective-C.

score 70 · Accepted Answer · answered Sep 24 '09 at 01:37

70

An enum is a plain-old-C type, therefore it provides no dynamic runtime information.

One alternative is to use the last element of an enum to indicate the count:

typedef enum {
    Red,
    Green,
    Blue,
    numColors
} Color;

answered Sep 24 '09 at 01:37

Darren

25,520
5
61
71

13

Good for contiguous values, utterly fails for `typedef enum { Red=0xff0000, Green=0x00ff00, Blue=0x0000ff, numColors} Color;`. – Mark Rushakoff Sep 24 '09 at 02:39
Like Mark said, this will fail big time for his example, the alternative provided by Darren is perfect for my needs. Thanks. – Josh Buhler Sep 24 '09 at 15:19
1

Look here for a better, completely automatic, but potentially dangerous solution: http://stackoverflow.com/q/24695580/269753 – Ricardo Sanchez-Saez Jul 11 '14 at 11:23

score 0 · Answer 2 · answered Nov 24 '21 at 06:28

Using preprocessors you can achieve this without the annoying 'hack' of adding an additional value to your enum

#define __YourEnums \
YourEnum_one, \
YourEnum_two, \
YourEnum_three, \
YourEnum_four, \
YourEnum_five, \
YourEnum_six,

typedef enum : NSInteger {
__YourEnums
}YourEnum;

#define YourEnum_count ({ \
NSInteger __YourEnumsArray[] = {__YourEnums}; \
sizeof(__YourEnumsArray)/sizeof(__YourEnumsArray[0]); \
})

Getting total number of enum items

2 Answers2

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