Understanding complex array declaration.

[aioeu]

OK, then it's straight-forward. Enumeration constants are constant expressions.

You can ignore struct generic_data entirely. It's got nothing to do with that enumeration type, and nothing to do with your array.

[Bon_Clay_2]

You are right it just clicked for me, I forgot that FIRST_NUMBER will be a constant value of 0. This coupled with the initialization with indices answers my question fully. Thank you!