Two enums have some elements in common, why does this produce an error?

Question

I have two enums in my code:

enum Month {January, February, March, April, May, June, July,         August, September, October, November, December}; enum ShortMonth {Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec}; 

May is a common element in both enums, so the compiler says:

Redeclaration of enumerator 'May'.

Why does it say so? And how can I circumvent this?

Answer 1

Enum names are in global scope, they need to be unique. Remember that you don't need to qualify the enum symbols with the enum name, you do just:

Month xmas = December; 

not:

Month xmas = Month.December;  /* This is not C. */ 

For this reason, you often see people prefixing the symbol names with the enum's name:

enum Month { Month_January, Month_February, /* and so on */ }; 

Answer 2

I suggest you merge the two:

enum Month {   Jan, January=Jan, Feb, February=Feb, Mar, March=Mar,    Apr, April=Apr,   May,               Jun, June=Jun,    Jul, July=Jul,    Aug, August=Aug,   Sep, September=Sep,    Oct, October=Oct, Nov, November=Nov, Dec, December=Dec}; 

Which will have exactly the same effect, and is more convenient.

If you want January to have the value 1, instead of 0, add this:

enum Month {   Jan=1, January=Jan, Feb, February=Feb, ....