CODEWITHSUNDEEP
c++enums
Guraiya
Guraiya

Reputation: 33

Multiple enumerations

I was wondering if I could use different enumerations in the same file where one is already present?

For this project I have elements which act as a genre for a number of books. I want to create different story's for the books and create a 2nd enum for them. 

enum element {
    ICE, FIRE, EARTH, WIND, NONE
};
enum book stories {
    FK, IK, EK, WK, NONE
};

could this start issues with my compiler?

Upvotes: 1

Views: 79

Answers (3)

πάντα ῥεῖ
πάντα ῥεῖ

Reputation: 1

Leaving the syntax error caused by book stories aside, you can make your enum declarations unambigous by putting them into a scope:

struct Elements {
    enum element {
        ICE, FIRE, EARTH, WIND, NONE
    };
};

struct BookStories {
    enum book_stories {
        FK, IK, EK, WK, NONE
    };
};

Referring to Elements::NONE and BookStories::NONE would be unambigous then.

Another way to make enums scoped is to use enum class (since c++11):

enum class element {
    ICE, FIRE, EARTH, WIND, NONE
};

enum class book_stories {
    FK, IK, EK, WK, NONE
};

Upvotes: 1

okovko
okovko

Reputation: 1901

This is most generally solved by doing this:

typedef enum element_e {
  E_ELEMENT_ERROR = -1,
  E_ELEMENT_NONE,
  /* ... */
} element_t;

typedef enum bookstories_e {
  E_BOOKSTORIES_ERROR = -1,
  E_BOOKSTORIES_NONE,
  /* ... */
} bookstories_t;

So you can maintain C / C++ interop in your header files. If you don't have any C modules, use enum classes like the other answers describe.

Upvotes: 0

serkan.tuerker
serkan.tuerker

Reputation: 1821

Yes. The enumeration NONE is present in both element and book stories (btw, you cannot name your enums with a space inside).

enum class

Use enum classes if you want to use NONE in both enumerations.

enum class element 
{
    ICE, FIRE, EARTH, WIND, NONE
};

enum class bookstories 
{
    FK, IK, EK, WK, NONE
};

Then you use your enum like this:

auto elem  = element::NONE;
auto story = bookstories::NONE;

Upvotes: 2

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