How do I determine the number of the members in an enum?

Question

Using C++11; MingW; Ubuntu 12.04 LTS:

Given:

    enum TMyEnum
    {
        Enum_1, Enum_3, Enum_3
    };

What function will tell me how many members are in TMyEnum, in this case 3?

Answer 1

One trick is to provide a count item at the end such as:

enum TMyEnum
{
    Enum_1, Enum_2, Enum_3, 
    Enum_4, Another_Enum, 
    Enum_count
};

Then TMyEnum::Enum_count should provide the cardinality of your set of enumerations. Just make sure you add new enumerations before Enum_count. Example:

#include <iostream>

enum TMyEnum
{
    Enum_1, Enum_2, Enum_3, 
    Enum_4, Another_Enum, 
    Enum_count
};

int main() {
    std::cout << TMyEnum::Enum_count << std::endl;   
}

Output

5

Answer 2

If you're going to use it with default values, you can have like following :

enum TMyEnum
    {
        Enum_1, Enum_3, Enum_3, No_of_Enums
                                //^^=3
    };